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conditions. Just what constituent was removed, however, remained in doubt for many years. Rosentha126found that the material removed was a protein, and assumed that it was elastin. Alfred Seymour-Jones,26 in collaboration with Wood, studied the effect of bating with pancreatin and concluded that bating dissolves the elastin fibers of the grain membrane. Wilson and Daub2’ examined the bating action under the microscope and showed unmistakably that the elastin fibers were dissolved away completely by the action of pancreatin. They then made an exhaustive study of the rate of digestion of elastin fibers from calfskin as a function of concentration of enzyme and ammonium chloride, time, and pH value, which has reduced the control of thisoperation from one of the most difficult to one of the simplest in the tannery. The empirical method for determining the completion of the bating process is by noting when the swelling or plumping of the skin has been entirely counteracted and the skin is quite flaccid. Wilson and Daub observed a point of minimum plumping a t a p H value of about 8. But Thomas and Kelly28and Porter29found the isoelectric point of collagen to be at about pH = 5. More recently Wilson and Gallun30 made a careful study of the plumping of unhaired calfskin as a function of pH value and found two points of minimum, one near 5 and the other near 8, the one near 5 having thelower value. This seems to indicate that what we call collagen consists of a mixture of proteins of very different isoelectric point, or else that collagen undergoes some internal change, possibly tautomeric, with change of pH value that tends to shift its isoelectric point. It has generally been thought that pancreatin is practically without action upon collagen, In fact Wilson and Daub could detect no appreciable destruction of collagen under the microscope while observing the complete solution of elastin. But F. L. Sey~nour-Jones,~~ experimenting upon hide powder, has found that under the right conditions and with sufficient quantity of enzyme, collagen is easily attacked and dissolved by pancreat,in. Wilson and Gallun have found that pancreatin will dissolve calfskin if given sufficient time. In one experiment they found no visible destruction of collagen for the first 24 hrs., but during the second day the fibers began to dissolve comparatively very rapidly, suggesting that the fibers possess a very thin surface much more resistant to tryptic digestion than the substance in the interior. The action of enzymes on skin during its preparation for tanning offers a fertile field for further research. J . Am. Leather Chem. Assoc., 11 (lele), 463. J . SOC.Leather Trades’ Chem., 4 (1920),60. 27 THISJOURNAL, 12 (1920),1087;13 (1921), 1137. 28 J . Am. Chem. Soc., 44 (1922), 195. 20 J . SOC. Leather Trades’ Chem., I (1921),259. 80 “Points of Minimum Plumping of Calfskin” (not yet published). 25
a* Advance note.
A final examination for appointment of second lieutenants in the Regular Army will be held the week beginning October 23, 1922, and appointments will be tendered successful candidates as soon as possible after December 31, 1922, in the following branches : Infantry, Cavalry, Field Artillery, Coast Artillery, Air Service, Corps of Engineers, Signal Corps, Quartermaster Corps, Ordnance Department, Chemical Warfare Service, Finance Department, and Philippine Scouts. Applicants must be citizens of the United States between the ages of 21 and 30 years. Each candidate is permitted to express his first and second choices of the branch of service in which he desires to be appointed, but the War Department reserves the right to make assignments in whatever branches of the service it may be necessary. Those interested may secure application blanks and further information from the Commanding Officer, Second Corps Area, Governors Island, N. Y., or the nearest military post.
Vol. 14, No. 9
Rare Organic Chemicals By H. T. Clarke EASTMAN KODAKCo.,ROCHESTER, N. Y.
Y “rare organic chemicals” is here understood chemicals required in relatively small quantities exclusively for laboratory purposes, whether for chemical research, analytical work, or experimentation in medical or physical science. Certain of the chemicals employed in pharmacy, perfuming, flavoring, and other industries might reasonably be c 1 a s s e d under this head; but in this article the above definition will be followed, to thc exclusion of all industrial products. The history of the progress of the nianufacture of this class of chemicals in the United States redly dates from eight years ago, when the supply from Germany ceased. Before that time practically nothing of the sort was made in this country, A m e r i c a n H. T.CLARKE chemists being content to draw their reqnirements, either directly or through supply houses, from the two important German firms which between them had built up the source from which the needs of the entire world were filled. When the pinch came, practically nothing was done during the first three years to relieve the situation, since the attention of chemical manufacturers was necessarily directed to more urgent, a t any rate more spectacular, problems. The first step was taken in 1916 in the University of Illinois, when Prof. C. G. Derick inaugurated a vacation class in which, under his direction, the othcrwise inaccessible organic chemicals required during the coming year were prepared. This valuable work, which did not excite imitation in other universities,’ was continued in the same laboratory by Prof. Roger Adams, who was able to supply a certain proportion of the products of the Illinois laboratory to other universities. It was not until the latter part of 1915 that commercial firms began to enter the field. The first of these was the Eastman Kodak Co., whose action was followed by a number of concerns, in particular the Hey1 Laboratories, the Special Chemicals Co., and the Synthetic Laboratories of Chicago, organized for the specific purpose of manufacturing research organic chemicals. The success of these undertakings has of course depended largely on the cooperation of the manufacturers of those organic chemicals that are employed on a larger scale, and this has in all cases been cordially and generously accordcd. Manufacturers of crudes, intermediate?, and dyes, such as The Burrett Go., E. I. duPont, de Nemours & Co., The National Aniline & Chemical Co., the Calco Chemical GO., The Dow Chemical Co., The Monsanto Cbemical Works, The Sherwin-Williams Co., to mention but a few of the more
B
1 An exception should be made in the case of the University of Wisconsin in which a considerable amount of time has more recently been devoted to the preparation of chemicals for its own use.
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important, have continually furnished information as t o the already extensive, is apparently still in the infancy of its products they manufacture not only for sale but for their own possibilities. The admirable work carried out by the Hey1 use. The same has been the case with the firms manulactur- Laboratories-now incorporated with the National Aniline ing pharmaceuticals, perfumes, and flavoring chemicals. & Chemical Company-constitutes an almost unique achieveSome of these concerns have indeed contributed nobly by ment in this domain, the quality of their products surpassing putting in the markct, often without financial profit, lines those of the EuropPan laboratories. of pure organic chemicals for research and development] purClosely related are the indicators employed in the modern poses. This has been done by the U. S. Industrial Chemi- methods involving hydrogen-ion concentration. The works cal Co. (pure alcohols and esters), the Fries & Fries Co. of Clark and Lubs, of Acree, and of Walpole have dernon(pure acids and esters), the Digestive Ferments Co. (rare strated the great value of the sulfonphthalein family of indisugars for bacteriology), and the General Motors Research cators (which, by the way, are also employed in experimental Corporation (hydroaromatic compounds). medicine), and this series of dyes has been well taken care Valuable work has also been done by certain firms who have of by the PYrolectric Instrument CO., The Ckkman and made readily available certain compounds that, had hitherto Bell CO., IlYnson, M’estcott a d Dunning, and l k l k ~ t t e been c1assc.d as ‘[pare chemicals.” Thus, The now Chemical Chemical Products CO., all of which also manufacture the Company now produces pure ethylene glycol, ethylene more important of the other indicators. It is difficult for the average chemist in his laboratory to chlorohydl*in and its acetate, and dichloroncetic acid; the Standard Oil Company and Carbide & Carbon Chemicals keep himself infqrmed of the various products that are availCorporaticJn have rendered isopropyl alcohol as accessible a able; and to assist such workers a list of American Research solvent as ethyl alcohol; while the Hirsch Laboratories have C k m & ~ l shas been Prepared under the aUsPices of the placed on the market a series of aliphatic amines and their National Research Council by Dr. Clarence J. West. It would be difficult to exaggerate the value of this list, which derivatives. With regard to the avomedly rare, and therefore generally is published annually and contains the name of every availexpensive, organic chemic&, the greatest number have been able chemical, toget’ler wit11 an index number for the firms prepared i n the Research Laboratory of the Eastman Kodak from which it can be obtained. Dr. West certainly deserves gratitude of every chemist for the admirable way in which c0.,Tvho now have list of Over 1300 different chemicals, the No attempt has been made to develop any special line, for he has discharged his laborious task* for the Preparaa’s0 being given to the object has been to prepare only those chemic& that are not produoed commercially on a technical scale, and to build tion Of a number of ‘are organic chemicals. In the Organic up as long a seriesof rare organic chemical.1in as short a time chemical manufactures of the University of Illinois, to which During the past 12 mo., 253 ew chemicals reference was made above, a number of chemical reactions as have been added to the list, of which 187 mrere prepared in are studied, and reports of these have been published annually Bulletin Adams, 0. the Eastnlan Kodak ~ ~ ~ The bremaining ~ 26~ per ~ in the ~ University ~ ~of Illinois i ~ ~ by Roger . Kamm, and c. s. Marvel. The information contained therein cent can be accounted for principallv by the vowtll of the range of organic chemicals produce& t~,,hnica1ly. It is in- is of great value to all chemists engaged in organic research teresting to note in this connectionthat the list of Kahlbaum work. Another series of annual publications, also stimulated containsthe names of just over 2000 organic chemicals, so into existence by Dr. Roger -4dam~,d e s W with the Prepsthat to reach this number not nlucll more than three years ration of organic chemicals, is that entfitled “Organic Synmore should be necessary. There can be little doubt, mopover, theses” (John Wiley & Sons). This is a more elaborate work, that the manufacturers of rare organic chemicals in G~~~~~~ in which each of the preparations described has been drawn up so as to leave no possibility of doubt and nzistake in proare (or were) able to dram. upon a much wider group of mercial chemicals than has yet been possible in the United cedure, nnd has been csreful!y checked by a member of the board* States; this would explain the occasional startling differences in price between certain German chemicals and the same products listed as rare chemicals in this country. The Public Health Institute of Chicago has undertaken to One of the most spectacular fields of rare organic chemicals is occupie(iby the sugar family. The production of these finance the cooperative research between the University of Wisconsin Medical School and the Chemical Department of Northcompounds constitutes almost a speciRl branch of chemistry western University, which in the past has been supported by in itself, arid there are few organic chemists who would dare appropriations from the U. s. Interdepartmental Social Hygiene to enter this field without special preparation. American Board. This research, which has been devoted to attempts to chemists and bacteriologists are tl1us greatly indebted to the improve the treatment of syphilis of the central nervous system, has been directed by Dr. W. Lee Lewis and Dr. F. C. Whitmore Digestive Ferments Company to the Specirtl of Northwestern University, and Dr. A. S. Loevenhart and Dr. Company for their fine work in making available an exten- W. p. Lorenz of the University of Wisconsin. The public sive list of the uncommon sugars in pure form. The amount Health Institute has appropriated $21,600 for the use of both of skill and labor necessary for their preparation and the ur- universities during the coming year. gency with which they are required for special work may be estimated from their cost, which in certain instances amounts to several dollars per gram. An allied field is represented in A series of lectures on the Geology of Commerce and Industry the amino acids required for and physio- is to be given by Dr. Ernest R. Lil]ey at the School of Commerce, logical rescarch. Here again valuable services have been N~~ york University. During the fall term the commercial rendered by the Special Chemicals Company and the Ab- geology of the fuels, chemicals, and building materials will be bott Laboratories, as well as by certain private workers, discussed in a nontechnical manner, covering for each of the commodities the properties and uses, methods of exploita. ~who~has ~ , in phypiological- basic notably ~ 1H.~J. B tion and conservation, including mining and preparation for chemical reagents of the meticulous degree of Purity required market. and the relation between market Drices and Droduction for such work. costs. ’During the spring term the lecturer will treai the comgeology of the metals, dividing the subject as follows: Another highly technical branch of chemistry which has mercial the iron group, the nonferrous metal group, the precious metals, collaborated with the medical sciences is the production of and the process minerals. Stress will be laid upon the nature bacteriological and medicinal dyes, an alliance which, while and cost of smelting and refining.
