REPORT
FOR ANALYTICAL
CHEMISTS
The Nature of Analytical Chemistry Harold G . Cassidy, Yale University, New Haven, Conn. r p H E term, "analytical chemistry," •*- m a y mean several things. I t refers to the professional activity of chemists who call themselves a n a lytical chemists. I t refers to t h e body of knowledge and experience developed by those people. I t is the name of t h e journal you are now reading, which is devoted to publishing this body of knowledge and experience. Analytical chemistry thus refers to an activity a n d to t h e results of t h a t activity, as well as to an organ for communicating those results. If these definitions are accepted, then we can clarify a number of questions facing those who are concerned with t h e future of analytical chemistry. If we define analytical chemistry as t h e professional activity of a n a lytical chemists, we have progressed only to t h e problem of defining an analytical chemist. This proves t o be difficult. I t is a problem of t h e kind faced by members of every professional group, whether lawyers, physicians, or engineers, who recognize t h a t their status is achieved and maintained only in conjunction with the acceptance of civic responsibility. I t is a problem t h a t needs to be dealt with continually because the professional m a n is continually under pressure from status-seeking groups who would like to use his good name, hard-won and maintained with effort, t o raise their own status. Some years ago in Connecticut, for example, a janitors' organization tried to appropriate the title '"'custodian engineer." W h a t e v e r t h e motives for such a semantical operation, it was clearly not in t h e public interest t o allow the word "engineer" with its implications of long training in theoretical and applied areas of knowledge and experience to be used in this way. Returning then t o t h e question " W h a t is a n analytical chemist?" we find, as with other professional groups, t h a t t h e definition m a y be set u p in several w a y s : b y enumeration, by the application of
principle, a n d b y a combination of the two. E a c h h a s its advantages and disadvantages. P e r h a p s a brief look a t each will p u t our problem in perspective. T h e solution of this problem in one of its more practical forms, by the w a y , determines w h a t kinds of papers shall be published in ANALYTICAL
CHEMISTRY.
Enumerative Definition The enumerative t y p e of definition, which is designed to tell when a person qualifies for a given title, lists in detail t h e training required and t h e duties to be performed. F o r a n analytical chemist, t h e training might be listed as a B.A. or B.S. from a college or university whose chemistry department is a c credited by the American Chemical Society. This is obviously not satisfactory, because, like a n y enumerative definition where w h a t is defined is in process of active growth, it becomes effectively a straight jacket. Such a statement, for example, would exclude from the charmed circle of chemical a n a lysts people who h a d graduated with B.A. or B.S. in physics or biochemistry. T h e casual reader m a y be inclined t o dismiss these statements as fine examples of tilting a t straw men, b u t the fact is t h a t such difficulties lie at t h e root of one of our problems. As a n illustration, now t h a t t h e advent of rapid problemsolving machines h a s brought t h e burden of necessary calculations within bearable limits, t h e x-ray method for structure analysis of organic compounds is becoming one of t h e most powerful tools we have in organic chemistry. Does this not signal t o us t h a t physicists, as these analysts of t h e x - r a y p a t t e r n a r c likely to call themselves, should be encouraged to publish in this a n d other analytical journals? Of course it does, a n d t h e same considerations apply to other scientific disciplines. Yet with a narrow definition of analytical chemistry such work will
continue t o be published in journals which are not so available t o chemical users as is ANALYTICAL
CHEMIS-
TRY. Furthermore, old categories have broken down and what was once chemistry has diffused into physics and biology and much else, and these have diffused into each other. I n such a situation an enumerative definition can be useful only as a stopgap measure. Straight enumeration can fail in another w a y . Sometimes w h a t is done is to list the activities t h a t define the particular professional man. Thus t h e analytical chemist could be defined by summarizing all t h e types of activities t h a t h a v e been reported over the last so-many years
in
ANALYTICAL
CHEMISTRY
and stating t h a t whoever does a n y of these is an analytical chemist. This t y p e of enumerative definition has two weaknesses. First, it generates a straight jacket. Some years ago, I am told, engineers who wanted t o be licensed in their t r u e capacities as aeronautical or n u clear engineers, found t h a t there were no such categories in the list of licensablc types of engineering. So the men involved h a d to enter their professions under existing license categories while t h e enumerative lists went through the slow legal processes necessary t o correct them. The second weakness is probably an unavoidable one, since it h a s t o do with quality. There is no a b solute criterion for the quality of work which will be accepted as "analytical." T a k i n g the most favorable case, where the analytical chemist has been as careful as possible—where he has tested each step in a procedure, looked for possible hidden sources of error, repeated t h e work m a n y times under widely different conditions which bracket those that might be encountered in the actual work— oven here we find qualitative differences between analytical chemists. Epistemological considerations would take us too far from our present discussion. Suppose, however, t h a t we use t h e terms " a n a VOL 32, NO. 4, APRIL 1960 ·
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REPORT FOR A N A L Y T I C A L CHEMISTS
lytical chemist" and "things ana lyzed" in their broadest senses as we will define them later. Then, using journal articles as our data, we certainly may postulate that in the interactions between these there is a distribution of qualities such that, were we able to plot "increas ingly high quality" along an χ axis and "frequency of finding it" along a y-axis, we would get a probability curve. There would be a few "poorquality," a majority of "good," and a few "superb." Parenthetically, editors and reviewers continually endeavor to skew this curve in the good-to-superb direction. This figure is drawn in an attempt to indicate that there is an inevit able relativeness in all judgments of quality. And even if we could present actual data with which to draw such a curve, we would be faced with deciding the break point : "above this, quality acceptable; be low it, not." But we would not find general agreement where this point should lie on the x-axis, for the problem is far from simple. Consider the analysis of copper. A new method, to justify publica tion, might well be required to show some special feature, such as great precision, exceptionally wide a p plicability, unusual rapidity, or use of a new technique or instrument. Yet in some other instance, where no one had previously been able to capture an elusive quality and re duce it to numbers, even the first tentative paper which points a pos
sibly fruitful line of approach might be high in this quality—mostly of inventiveness or, perhaps, inge nuity—which makes it analytical. Such matters of quality defy enu meration and elude prediction. They are matters for judgment. Thus we reaffirm t h a t we cannot define analytical chemistry by enu meration. We also reaffirm that judgments are made by people op erating on the basis of general rules of conduct, thus we cling to the procedure by which an editor with the assistance of reviewers makes a decision. In this way we do our best to minimize the rejection of meritorious papers and the accept ance of those of poor quality. Definition by Principle The second kind of definition of the analytical chemist is based on principle: I t is a philosophical type of definition. It defines a t an a b stract level. Considering all things that analytical chemists do, or as many of them as possible, one at tempts to abstract the common principles from the welter of de tail. These principles are used as a basis for the definition. Thus a definition of analysis might be " r e duction of a complex whole into its parts." Analysis is then defined as whatever fits this principle. When the complex whole is chemical, we would have a definition of chemical analysis. Because it is abstract, this kind of definition tends to avoid
Dr. Harold G. Cassidy, 54-year old Professor of Chemistry, Yale University, was born in Cuba in 1906. He received his A.B. from Oberlin College in 1930 and his M.A. in 1932. He taught at Oberlin in 1932 to 1933 and again in 1936 to 1937. Between these two periods, he was a research chemist at W m . S. Merrell Co., Cincinnati. He joined the teaching staff it Yale in 1938 as an instructor. In 1939 he received his Ph.D. at Yale. In 1943 he became an assistant professor and in 1 9 4 8 an associate professor. He is now a full professor. He is the author of two monographs: Adsorption and Chromatography (1951) and Fundamentals of Chromatography (1957, Interscience), and co-author, with Professor James English, Jr., of Principles of Organic Chemistry (McGraw-Hill). His present chief research interests lie in the field of electron exchange polymers, a field of polymer chemistry invented and opened up by him and his students. He has been active in chemical education, especially with respect to the problems met in communicating the facts and philosophy of physical science to college students who are not initially oriented toward science. This month's Report for Analytical Chemists is the outgrowth of a talk given by him before the Rochester Section of the American Chemical Society in 1957.
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the straight-jacket difficulty. It can be very satisfactory, if inter preted in good faith. J u s t because it is abstract, it is uncommonly susceptible to abuse by semantical juggling. This is a potential source for failure of such types of defini tion. Definition through Compromise Again we return to the fact t h a t it is persons who in the final act must interpret and judge in these matters. We may, as an aside, note t h a t people of one predominant temperament will prefer the enumerative ; others, with another tem perament, will prefer the abstract type of definition. We must recog nize, also, that history has shown over and over again t h a t govern ment under law is superior to gov ernment by personality. Even though we have the most prudent and scrupulous people determining who is an analytical chemist and wdiat is analytical chemistry, they must operate under some guiding principles. Thus it is t h a t legal definitions m a y be set up. These usually are of a third type which consists of a blend of the first two— the enumerative and the abstract. The factual situation was stated succinctly during hearings held in the House of Representatives on the Federal Food, Drug and Cos metic Act of 1938. Mr. Walter G. Campbell, Chief, Food and Drug Administration, said, "There are
FREE DATA KIT certain inevitable conditions encountered in t h e enactment of regulatory legislation. There is t h e influence of t h a t group whose interest is dictated b y a concern for the public welfare. There is also the group whose interest is dictated by perhaps an equal public concern, but who also have selfish interests and who insist on seeing that abuses in administration cannot occur. And then there is finally tlie small b u t negligible element t h a t is opposed to a n y legislation a t all. T h e inevitable cross-pull of such influence results in compromise ( 5 ) . " T h e legal definition, if a n y , must be a compromise. Certainly it cannot usually be purely an a b s t r a c tion, since such abstractions usually do not fit very justly the exigencies of the m a r k e t place. T h e same kind of problem was encountered almost 100 years ago in early days of the Society of P u b lic Analysts in England. The most pressing evidence of t h e need for a strong society of objective and competent analytical chemists lay in the realm of food a n d drug adulteration. At the first meeting in 1874. (3) members set up a committee to define "adulteration." T h e committee had many meetings, and finally reported back to the society (.fl. I t h a d been unable to construct a definition of adulteration ''at once comprehensive enough to include all actual adulterations a n d at the same time sufficiently elastic to prevent oppression or injustice." Instead, it laid down a statement of what should constitute an adulterated article. Here, then, we see t h a t t h e definition of an abstract a n d general concept could not be made t o meet the requirements of this quite dedicated group. I t h a d to turn t o a p a r t l y enumerative statement. T h e two horns of the dilemma are avoided to the greatest extent possible by making necessary legal definitions—which avoid a straight jacket without being too discretionary. T h e problem of definition has arisen for professional engineers, who are licensed. I n the General S t a t u t e s of Connecticut t h e following is given: "For the purposes of chapter 225 of the general statutes, ''professional
engineer' means a person who is qualified by reason of his knowledge of mathematics, the physical sciences and the principles of engineering, acquired by professional education and practical experience, to engage in engineering practice, including the rendering or offering to render to clients any professional service such as consultation, investigation, evaluation, planning, design or responsible supervision of construction, in connection with any public or privately owned structures, building, machines, equipment, processes, works or projects wherein the public welfare or the safe-guarding of life, public health or property is concerned or involved . . ."(6).
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Notice t h e enumeration and a b straction. T h e definition just quoted goes back to the source of t h e qualification a n d to the definition of engineering. T h e Engineers' Council for Professional Development proposed this definition: "Engineering is the profession in which a knowledge of the mathematical and physical sciences gained by study, experience and practice is applied with judgment to develop ways to utilize, economically, the materials and forces of nature for the progressive well-being of mankind." (1). T h e m a t t e r of qualification is usually the responsibility of a board of one's peers. N o t i n g t h e problems t h a t engineers have been forced to meet to protect themselves m a y seem somewhat removed, in appearance, from our initial objective. I t is, however, relevant from a functional point of view, since it points u p the problems we have tried to a n a lyze. T h e lesson this teaches is t h a t the present structure of t h e American Chemical Society and ANALYTICAL CHEMISTRY is close to the optim u m kind. I t is very doubtful whether perfection can be achieved in this world solely by means of definitions. I t can be approximated only if in t h e minds and hearts of professional men there reside principles of integrity, and wisdom and firmness sufficient to require adherence to their ethical codes. This is the responsibility of all of us who create, practice, a n d teach a n a l y t i cal chemistry: We are the profes-
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REPORT
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Thus far we have suggested t h a t a definition of the analytical chem ist could neither be given purely by enumeration nor in a purely ab stract manner. Rather, it must be given in such a way t h a t it can reflect, through interpretation and use, changes in the field of a n a lytical chemistry as it grows. Ideally, changes in interpretation and use are brought about by all analytical chemists, by activities of the editors and reviewers of jour nals, and by contents of the jour nals. There must be criteria available to analytical chemists to identify their profession. This is particu larly important during periods of very rapid advances, because boundaries between divisions in science are not fixed and are far from sharp. Also, a rapidly grow ing area of science may extend itself to include large portions of another with unfortunate consequences to both unless, at the same time, a far-reaching synthesis occurs. These divisions are really cate gories of convenience: devices by means of which similar activities and related knowledge are held t o gether for the benefit of the mem bers of the group, as well as for the benefit of the science as a wdiole. They comprise, as we have noted, activities and results of activities and knowledge of the member scien tists. They tend to have a corpo rate organ for communication—a journal named for the division— when the group of members is large enough to support it. In the case of analytical chem istry, several trends are developing which suggest t h a t a clear picture of the nature of analysis and of analytical chemistry as it appears at present would be helpful. One of these trends is seen in the disap pearance, little by little, of classical analytical chemistry courses from the second year of the chemistry curriculum. This is important be cause what happens in school even tually overtakes the professions,
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and vice versa. This trend is partly a response to t h e pressures of "theory." Insofar as it involves the transfer of t h e educational values of analytical chemistry into other courses, with consequent enrichment of them, there is little t o oppose this trend. T h e criteria we will develop will show what these values are. Another trend is generated by the success of our profession as it is manifested on t h e technological side. AVe see as a reflection of this trend t h e development, in increasing numbers, of courses in instrumental analysis. Where these courses are courses in analysis, rather than courses in following the directions for t h e manipulation of machinery, little can be said against, such a trend. If, however, we should observe t h a t t h e analytical aspects of chemistry are being lost sight of because of the pressures of theory, or are being derogated through identification with some notion about ''cookbooks," such an eventuality should be combated in the name of chemistry itself. Analytical chemistry is one of the three great interlocking aspects of chemistry a n d damage to it would d a m age the others and the whole.
Analysis
To see analytical chemistry clearly, we shall have to observe t h a t " a n a l y s i s " or " a n a l y t i c a l " are words with m a n y meanings—meanings which change significantly with the context in which they are used. In scientific language an endeavor is made to get away from such words. B u t older words in science tend to have clinging to them festoons of connotations which are carried around as a burden when the word is used scientifically. Such connotations perform import a n t functions in nonscientific usage, as in literary or poetic use. We will therefore define and qualify the use of " a n a l y s i s " and " a n a lytical" for our purposes here. Analysis is generally defined as the resolution of a thing, or a complex whole, into its elements or component parts. I n classical chemical analysis t h e thing, or complexwhole, is usually conceived as a
REPORT FOR A N A L Y T I C A L
CHEMISTS
mixture or a compound which is separated by physical means, or broken down b y chemical means, into simpler or more recognizable parts. B u t the complete chemical analysis also involves deductions about t h e original n a t u r e of t h e complex whole. These are based on much more t h a n a mere resolution into elements, or simple parts.
They involve finding out what these parts arc—qualitative analysis; how much of each is present—quantitative analysis; and what their relationship to each other was in the complex ivhole—relationslnp, or structure, analysis. T h u s classical analytical chemistry involves much more t h a n t h a t defined in a dictionary, which is the
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legal definition of analysis. I n some cases qualitative analysis cannot easily be distinguished from quantitative. This happens when the difference is one of degree only. Nevertheless t h e two categories a r e clearly convenient ones. The T h r e e A s p e c t s o f C h e m i s t r y
We can throw light on t h e question by considering the activities of chemists a n d chemical engineers. W h a t we will s a y applies to most types of creative h u m a n activities, but t h a t is a m a t t e r beyond our present purview. Empirical knowledge usually develops out of activities which we will call " a n a l y t i c . " Such activities involve not only taking apart, b u t also collecting, describing, cataloging, and measuring. All of this we will include as " a n a l y t i c " activity. At the same time t h a t this is going on, however, these " a n a l y s t s " begin to see connections between t h e things, or t h e facts, t h a t they collect. This leads t o dividing them into classes. As the process continues, and more connections are seen, hypotheses, theories, and laws a r e developed. Thus " a n a l y t i c " activity imperceptibly shades over into a generalizing, relationship-finding activity, which we will call "synthetic." When these terms appear in quotation marks we will be using them in t h e meanings given here. These two activities go hand in hand. W e have artificially separated them here only for the purpose of discourse. F o r this reason, too, we separate t h e third activity: "reduction t o practice." Knowledge is sought for use, and as t h e " a n a lytic" and " s y n t h e t i c " activities lead together to greater control over nature, use is made of this by r e turning from t h e general principles, theories, and laws to t h e phenomena themselves. This is also an activity of many analytical chemists. Teaching it is t h e principal function of the laboratory course. The process can be looked at in this w a y . Working with r a w d a t a , the chemical " a n a l y s t " gathers, sorts, catalogs, analyzes, measures, and classifies t h e data. If they are "things"—rocks, ores, plant a n d animal materials, a n d so on—he has not only to gather and sort
REPORT FOR ANALYTICAL CHEMISTS then), and put them into museums where teachers can point to them anil say, for example 1 , "This is what we mean by 'cinnabar,' "' but he has also to devise, invent, create symbols for them. The difficulty of accomplishing this is what has held chemistry back compared with physics. As historians have pointed out, < îalileo and later scientists were
able to set aside the question and concomitant point of view ''why does this event occur?'' in favor of the question and point of view "how does this e\'ent occur?" In the process, they were able to create means for answering this question. For example, by investigating a ball rolling down an incline, they were able to establish a mathematical re-
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lationship between time and distance. By inventing thoughtexperiments such as "thinking a w a y " the effects of friction on the ball, simple relationships could be seen. And they had. ready at hand, a well developed mathematics available for their use. They had to learn or invent how to make the symbolic transformation from the raw data and the thought experiment to mathematical terms. But chemists were people concerned with qualities as well as quantities. It made no difference to Galileo's conclusions whether the rolling ball was polished bronze or silver, but in a chemical reaction the nature of the reagents is crucial. It has been the difficulty of making the symbolic transformations, from observed qualities to symbols by means of which they can be manipulated, which has held chemistry back. The reason is that not just any symbol will do; one has to have symbols which correspond in some fundamental way to a property which enables the whole held to be classified: a property which leads to what John Stuart Mill called a natural classification. We have seen such a classification develop through Mendeleev. Moseley. Pauli. and others, to one of the greatest generalizations in science the modern periodic classification. By the time he has begun to classify his data, the " a n a l y s t " has already begun to carry out "synthetic" activities. "Synthetic" activities, in the sense in which we have defined them, rely absolutely upon " a n a l y t i c " activities. The generalizations which are the fruit of this activity are based on. and must be tested against, the data. All these activities go hand in hand: each would be sterile without the others. The third activity, "reduction to practice," clearly goes with "analysis" and "synthesis." In the early days of science a chemist usually carried on all three. However, as more came to be known in each area, specialization tended to sepa r a t e the functions. Analytical chemists tended to be separated from theoretical chemists, both or-
REPORT
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ganic a n d physical. Members of the latter group, practicing predom inantly t h e two types of activities, were thought of more or less as pure chemists. I n turn, they were sep arated from t h e applied chemists, the technologists, or chemical engi neers, who reduced "pure chem istry" to practice. These are arti ficial categories embodied in insti tutions—societies, divisions, depart ments—because this is useful. B u t it is most important to recognize that they are artificial a n d t h a t the three activities are not comparable. The pure chemistries a r e neither better nor worse than t h e applied— only different. T h e three are m u tually complementary a n d supple mentary. T h a t all three activities are sup plementary and complementary to each other becomes very evident when t h e activities involve some thing beside chemicals—when they involve symbols a n d concepts. F o r the triad of activities can operate a t all levels of abstraction within the domain of each activity. Hence the chemical engineer h a s courses in the theory of reduction to prac tice, as well as in t h e " a n a l y s i s " of his methods and the "reduction to practice" of his theory. Likewise, a theorist in chemistry engaged in " s y n t h e t i c " activities m a y well be concerned with the " a n a l y t i c " a p proach t o his theories, b u t a t t h e level of investigative activity. He is also concerned as well with "higher" synthesis and its applica tion. W e see, then, t h a t analysis a s it is used in chemistry h a s broad meaning. I t comprises qualitative, quantitative, a n d relationship com ponents. I t applies not only a t t h e level of substances, b u t also a t t h e level of concepts by means of which substances are manipulated b y t h e intellect. I t applies also a t t h e levels of generalizations of concepts. "Analysis" must in t h e nature of things precede "synthesis," or theory, in t h e temporal develop ment of any natural science. Hence there is a tendency for chemists on the theoretical side to see theory as in some w a y purer, or higher, t h a n "analysis." Bound u p in this a r e m a n y legacies from the past—works of t h e hands a r e less noble t h a n
REPORT
those of the head; working with things which dirty the hands is less elevating than manipulating symbols. This can lead to a separation of the two, when they should always be kept connected. I t is invidious and snobbish to derogate one of these activities with respect to another. Comparisons can be made legitimately only on the quality of the work: whether it is imaginative, original, sound. It is worth recalling that Anaxagoras said in the fifth century B.C.. that it was through possessing a pair of hands t h a t man became wise.
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I t is, however, through the combination of " a n a l y t i c , " "synthetic," and "reduction to practice" activities t h a t pure science advances. As facts accumulate to the point of unmanageability, there is more recourse to theory. In p a r t this is why purely descriptive courses in chemistry have given way more and more to theory courses. The old analytical chemistry and descriptive inorganic and organic have been transformed into physical chemistry and physical organic. This trend was evident in the twenties in Professor William H. Chapin's very successful text and laboratory manual in second-year chemistry which was half physical chemistry in nature (2). It is evident also in the recent emphasis on mechanisms in organic chemistry. I t appears t h a t the proportion of descriptive chemistry in college courses has decreased continually. This has been one of the pressures put on the high school course: to provide the descriptive chemistry which is left out of the college courses. Indeed, some educators rem a r k t h a t the modern chemistry major course begins in high school. The foregoing examination of analysis is by no means complete, but is intended to clarify some of the issues involved in any consideration of the future of analytical chemistry. I t seems to confirm present practice, on the whole, and to suggest directions in which it would be desirable to move. Values
Qualitative, quantitative, and relationship analyses are clearly the functions of the analytical chemist,
REPORT
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but perhaps a broader interpretation needs to be given to these functions. At the level of material things—elementary substances, compounds, and mixtures—there is perhaps a need for more emphasis on relationship analysis. This could be met by emphasizing the information on relationship that some of the newer techniques—infrared, nuclear magnetic resonance, x-ray, and optical spectroscopy—can give. It is quite possible, too, that explicit recognition should be given now to the analytical functions at the levels of symbols and concepts: e. g. through the use of set-theory. This suggestion will bring some disagreement among chemists. Yet it deserves consideration for the following reasons, all of which return us to the observations about current changes in emphasis in analytical chemistry made earlier in this essay. If we can rightly maintain that the triad of activities—"analysis," "synthesis," and "reduction to practice"—are inseparable parts of chemistry, and that increasing specialization born of, and bearing, increased knowledge tends to separate these activities with loss to all, then it would seem that a move which counters this division is desirable. One partial move in this direction appears to be occurring through changes in some college curricula. This move is to drop the classical second-year course in analytical chemistry and introduce its values into other courses. These values are usually described as "the quantitative approach," usually applied to dealing with materials in the laboratory. We have seen that "analysis" is much more than this. We would suggest that the journal, ANALYTICAL CHEMISTRY, could assist in these changes editorially by examining the trend from time to time, and emphasizing repeatedly the values of the analytical part of chemistry. These values arise through the proper functioning of the whole of chemistry, where our triad of activities reinforce each other. (Values, in general, result from the proper functioning of whole systems, but this more general matter is outside our present scope.) Thus it is important to see that the values
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REPORT of analytical chemistry m a y be transferred to courses, making them broader and deeper when "analysis" and "synthesis" activities are com bined and reduced to practice in the laboratory, and when these ac tivities are themselves analyzed and generalized a t more subtle levels as the training of the chemist con tinues. A further conclusion is t h a t the journals might consider accepting a limited number of articles of a genuinely " a n a l y t i c a l " nature which deal with concepts and laws— papers which would not necessarily be classified as philosophical. Such papers might explore the heuristic aspects of analytical chemistry. I t would probably be very difficult to find such papers which would at the same time be acceptable, but it would be an encouraging and farsighted move.
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Conclusion The profession of analytical chemistry embraces the whole of chemistry with respect to its values, but in emphasis is restricted to " a n a l y t i c " activities. These can not be conceived as limited to chemicals only, but embrace the analysis of theory and of practice. As long as analytical chemistry is t a u g h t and practiced in the light of its total role in the profession of chemistry it will continue to prosper and grow with the profession as a whole. Acknowledgment I a m indebted to Professor An drew Patterson, Jr., of Yale Univer sity, for discussions bearing on this essay. Literature Cited
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(1) Am. Soc. Civil Engrs., Ann. llept., p. 11, 1958. (2) Chapin, W. H., "Second Year Col lege Chemistry," Wilev, New York, 1922. (3) Chem. News, Aug. 14, 1874. (4) Ibid., Dec. 11, 1874. (5) Dunn, C. W., "Federal Food, Drug and Cosmetic Act of June 25, 1938," p. 1273, G. E. Stechert and Co., New York, 1938. (6) General Statutes of Connecticut, Public Act No. 546, Chap. 225, 1957.
