February 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
219
of the circulating acid fraction had dropped to about 5%. As the acid concentration decreased further by reaction with nicotine, the extraction dropped off somewhat, but was still about 67% when the product was nearly neutralized a t a p H of 5.15. Most of the entering nicotine is therefore recovered in the first stage, at least until the acid is almost all neutralized. Hence, i t should be practical to operate both stages continuously, feeding slightly more than the required acid to the second stage, drawing product from the first stage a t a p H of 5.1 to 5.2, and neutralizing the unreacted acid.
would be lost during clarification of the juice and possibly 2% each in the kerosene extraction and acid-contacting steps. Attaining higher yields in the pressing and clarification steps would result in increased dilution of the juice. Loss during extraction with kerosene is largely due to incomplete extraction of the juice and could be reduced by increasing the column height, if this is economical. Actual loss in the acid-contacting section would be primarily due to handling, because nicotine sulfate entrained throQgh the settling chamber would be recovered ultimately by being recycled with the kerosene.
Discussion
Acknowledgment
This work illustrates a new process for recovering nicotine from green plants containing substantial amounts of nicotine, which can be expressed effectively. The general process may also be applicable to the isolation of valuable constituents from other plants, provided that these constituents can be expressed in the liquor and a suitable immiscible solvent can be found. All steps in the process operated satisfactorily. With the exception of expression of juice, all operations can be carried on throughout the year. The process eliminates the necessity of drying the plant material, and substitutes expression of juice for the steam distillation step conventionally employed with tobacco stems. The over-all recovery of nicotine from the green plants can be relatively high, but in practice it will probably not be economical to recover more than about 85%. The largest part of this, about 8%, would be lost in the expression of juice. About 3%
The authors are indebted to E. G. Beinhart for various suggeations and for supplying the Nicotiana rustica plants, and to C. 0. Willits and J. A. Connelly for the analytical data. literature Cited (1) Perry, J. H., “Chemical Engineers Handbook,” 2nd ed., p. 1254,
New York, McGraw-EH Book Co., 1941. (2)Phillips, C;. W.M., et al.,“Cane Milling and Pressing of Nicotine from Nicotiana rwtica,” manuscript in preparation. (3) Willits, C. O.,Swain, M. L., Connelly, J. A., and Brice, B. A., Anal. Chem., 22, 430 (1950). RECBIVBD September 20,1951. Report of a study made under the Research and Marketing Act of 1946 by Eastern Regional Research Laboratory, one of the lsboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.
Metabolism of Nicotine and Nature of Tobacco Smoke Irritants Virtually all absorbed nicotine is eliminated from the body in the urine, about 10% being excreted as unchanged nicotine and the rest in chemically altered form. Enzymatic processes are involved in the detoxication of nicotine, and the liver, kidneys, and lungs are the most active sites. The detoxication products are unknown but evidence points toward the splitting of the pyrrolidine ring of the nicotine molecule. Nicotine i s the most important tobacco smoke constituent in producing the acute subjective sensation of throat irritation. Edema formation, often used experimentally to measure smoke irritation, does not reflect the irritating actions of nicotine and is probably a result of the complex mixture of acids, aldehydes, etc., in tobacco smoke.
P. S. LARSON Medical College of Virginia und American Tobacco Co., Richmond, Vu.
T
HE major portion of absorbed nicotine is detoxified within the body and only in part is the molecule eliminated unchanged in the excreta and secretions. The information reported here concerns that part that is eliminated unchanged. ,Metabolism of Nicotine by the Animal Body
Excretion in the Urine. Evidence for the presence of nicotine in the urine of individuals exposed to it has been achieved through isolation of it as the dipicrate and identification by melting point (16),isolation as the picrate and picrolonate iollowed by chemical and pharmacological identification (6),and isolation as the oxalate and picrate with identification through melting point and empirical formula determinations (22). Quantitative estimations on the urine of tobacco users show that the amount of absorbed nicotine excreted unchan,ged is of
the order of 10% or less (3, 18, 60, 61). This amount varies somewhat with the pH of the urine (18), less being excreted unchanged when the urine is maintained alkaline (about 2 to 4% a t pH 7 to 7.5) than when it is maintained distinctly acid (10 t o 13% a t pH 5 to 5.5). The explanation offered is based on the pKn of nicotine which is such that large changes in the ratio of free to combined base are produced by variations in p H within the range compatible with living tissues. The free base is much more readily absorbed from the urinary tract than are salts of nicotine, and hence a t the higher urinary pH’s more of it may become re-exposed t o detoxication within the body. Studies on the dog show that the per cent of administered nicotine excreted unchanged in the urine increases with increasing -nicotine dosage (13). Thus, whereas the per cent excreted in the urine averaged only 6.7% following 3 mg. per kg. doses, following
INDUSTRIAL AND ENGINEERING CHEMISTRY
280
15,24,and 48 mg. per kg. amounts, i t rose t o 13.7,20.0, and 30.4%, respectively. This is to be expected from the finding that with increasing nicotine concentration the rate of urinary excretion uf nicotine increases linearly, whereas rate of detoxication within the body increased logarithmically. Evidence has also been presented for the dog and the rabbit (35) and for the rat (49)that chronic exposure t o nicotine leads t o a decreased percentage excreted unchanged in the urine. Table 1.
Relative Rates of Detoxication of Nicotine by Tissues from Several Species of Animals
[Assembled from data published by Werle and coworkers (44-46, 48, 4 8 ) ] % of Added Nicotinea Detoxified by Species Liver Lung Kidney Brain Approx. 40 Approx. 15 Rabbit 100 Approx. 50 0 .. Sheep 100 0 Approx. 25 Pigeon 90 26 17 '0 Guinea pig 57 17 0 40 Dog 16 10 40 Cat 25-30 10-25 10116 Man 35-42 14 5-8 10 30 Rat Pig zt 0 0 0 0 .. Cattle 0 Based on adding 0.4 or 0.5 mg. of nicotine in 0.5 ml. of water t o 0.8 gram of or an in 3 ml. Tyrode's solutlonI and incubating under oxygen for 3 hours a t 3% C.
.. I
.
..
Secretion in Milk. Identification of nicotine in milk has been largely by biological rather than by chemical techniques. In one study (9),in which subjects smoked 6 to 15 cigarettes in a 1- to 2hour period, milk collected a t 2 to 3, 4 to 5, and 7 to 8 hours after smoking and assayed on the leech muscle preparation was found t o contain nil t o 0.03 mg. of nicotine per liter. In a second study (34) on subjects smoking 15 t o 30 cigarettes, in which the nicotine waa distilled from the milk and precipitated with silicotungstic acid, the maximum amount found was 0.013 to 0.015 mg. per liter. A third study (S6), using Daphnia magna for the bioassay of nicotine, gave rather divergently high results. Smokers of 1 t o 4 cigarettes daily gave an average secretion of 0.116 mg. per liter in morning specimens and 0.16 mg. in afternoon specimens. The corresponding figures for those smoking 5 t o 10 and 11 t o 20. cigarettes daily were 0.225,0.278,and 0.445,0.5 mg. per liter. Urinary concentrations of nicotine were found to be 11 t o 17 times greater than that of the milk. Two experiments on cows (21) gave the following results: A 455-m1. milk sample taken 1.5 hours after intramuscular injection of 2.183 grams of nicotine in four divided doses over a 3-hour period contained an estimated 0.1 mg. of nicotine. A specimen (of similar size) taken 5 hours after injection of 200 mg. contained only a trace of nicotine. Excretion in the Feces. One study (@) on rats indicates a fecal excretion of 6 t o 8% of administered nicotine, while a second study (17) on mice using radioactive nicotine indicates a considerably lower excretion by this route. Excretion in the Perspiration. KO reliable data are available on this subject, although there is no reason to doubt but that the body fluid concentration of nicotine is reflected in some proportion in any perspiration that forms. Excretion into the Air. The possibility of an appreciable nicotine elimination by this means cannot be considered seriously, for the volatility of nicotine from dilute solutions is very low. Sites of Detoxication of Nicotine within the Animal Body. The foregoing indicates that only a small percentage of absorbed nicotine is excreted unchanged by the body. The following studies bear on the sites of detoxication of nicotine within the body. As long ago as 1876, evidence was noted for the detoxication of nicotine by the liver (SO). This has been confirmed repeatedly (1,15,19,38).
The most extensive studies of a quantitative nature have been made by Werle and coworkers (44-46, 48, 49). The technique used was that of incubating freshly prepared tjssue slices of vari-
Vol. 44, No. 2
ous organs in Tyrode's solutioii containing nicotine, the amount of nicotine detoxified being determined by the amount not recoverable by distillation and colorimetric determination after a suitable time period. Table I, embracing their findings, has been assembled from their various publications. It is seen that, varying somewhat with the species of animal studied, liver, lung, kidney, and brain may be sites of detoxication of nicotine. Other tissues such as muscle, spleen, small intestine mucous membrane, adrenals, skin, and blood, studied in some of the species, failed to detoxify nicotine. Nature of the Detoxication Process. From the studies of Werle and coworkers referred to, the following information concerning the nature of the detoxication reaction haa appeared. The reaction is dependent on the intact cell, autolytic processes brought about by cell rupture inhibiting it. It is also dependent on the presence of oxygen and proceeds optimally a t neutral pH. It does not proceed in an atmosphere of nitrogen and can be inhibited by carbon dioxide, cyanogen (CN-), chloroform, sodium azide, methylene blue, oxyquinoline, and pyrophosphate. It is not inhibited by hydroxylamine or semicarbazide. Studies on the intact dog, excluding the nicotine excreted unchanged in the urine, have shown that rate of detoxication within the body bears a logarithmic relation t o nicotine concentration (IS). This was also shown t o be the case for guinea pig liver slices (47). It is concluded that an enzyme process is involved. Nature of the Products of Metabolism of Nicotine. Relatively little is known concerning the nature of the products of metabolism of nicotine. Early studies on nicotinic acid indicated an increased excretion of it (4,aU) as well as of trigonelline (SI,%) in the urine of smokers. Evidence that these results were due t o the nonspecific character of the analytical procedures used, excretion of unchanged nicotine, being reflected in them, soon appeared (11, ST). I n an experiment on the dog, designed to study the effect of administered nicotine on the urinary excretion of nicotinic acid, nicotinuric acid, trigonelline, and N-methylpyridinium hydroxide (a metabolite of pyridine), no increase in the excretion of these compounds over the control periods was found (28). Similarly, studies on the formation of nicotinic acid, nicotinamide, trigonelline, and Ar-methylpyridinium hydroxide from detoxication of nicotine by liver slices gave negative results (47). It vould appear from these studies that metabolism of nicotine to nicotinic acid or pyridine does not occur. I n a study on dogs referred to (28),it was noted that following nicotine administration the urine contains a compound that yields a red color when reacted with cyanogen bromide. Control urine does not contain this material and the reaction of nicotine with cyanogen bromide does not give this color. With this clue in mind, the behavior of some methylated and demethylated derivatives of nicotine were studied. llonomethyl-, isonionomethyl-, and dimethylnicotinium iodides did not give a red color when reacted with cyanogen bromide. Further evidence against the methylation of nicotine during detoxication appears in the observation that addition of methionine to liver slices being incubated with nicotine depresses the rate of detoxication (49). The demethylated derivative, nornicotine, did form a red color with cyanogen bromide. However, it cannot be the metabolite in question for this metabolite is not extractable from alkaline urine with ether, whereas nornicotine is. Further, the metabolism of nornicotine in the dog differs from that of nicotine in that its administration does not result in the presence in urine of an etherinsoluble substance giving a red color with cyanogen bromide. Production of a red color in the reaction between nornicotine and cyanogen bromide led to an examination of the behavior of products of cleavage of the pyrrolidine ring of the nicotine molecule (29). 3-(4-Methylamino-l-butenyl)pyridine,3-(4-methylaminobuty1)pyridine and 3-(4-aminobutyl)pyridine, representative of products of cleavage of the pyrrolidine ring between the
INDUSTRIAL AND ENGINEERING CHEMISTRY
February 1952
CO-NH--CHz-COOH
bH8 Trigonelline
Nicotinic acid
Nicotine
Nicotinuric acid
Q
/\
HO CHI N-Methy l-
yridinium ydroxide
E
Isomonomethyl nicotinium iodide
Monomethyl nicotinium iodide
Q
\ -CH=CH--(
Nornicotine
(J-(
CHz)a-NH-CH,
3-( 4-Methylamino-l-butenyl ) pyridine
CH~)~-NH~
,Q-~-(CH~)~-CH~
Dimethyl nicotinium iodide
0
\ -( CHZ)~-NH-CHI
3-(4-MethylaminobutyI) pyridine
,O-CH--(
CH~)~-CH~
d ‘CH, 3-(4Aminobutyl) pyridine
3-( 1-Methylaminobutyl) pyridine
l-m~;
3-( butyl) pyridine
281
ceivabiy, 4methylamino-3-pyridine butyric acid, 4-amino-3-pyridine butyric acid, and, through beta oxidation, %methylamino-%pyridine acetic acid, and %amino%pyridine acetic acid would all satisfy these conditions and all become possible nicotine metabolites. 2-Amino-%pyridine acetic acid has been tested and found to yield a red color on reaction with cyanogen bromide (unpublished data). Efforts t o isolate and purify this compound for identification have thus far been unsuccessful. However, it seems quite likely that it will prove to be only an intermediate in the further degradation of the molecule. Another viewpoint on the path of metabolism of nicotine arose from the findings that liver slices metabolize nicotyrine [ 3- ( 1 - m e t h y 1 -2-pyrryl)pyridine] much more rapidly than nicotine; that the enzyme system involved has the same characteristics as that for nicotine and that the metabolism of nicotine is conipletely inhibited in the presence of nicotyrine but that of nicotyrine is not affected by the presence of nicotine (46). This led to the view that nkotyrine may be an intermediate product in nicotine metabolism. Pursuing this further, the urine of dogs, rats, and guinea pigs receiving nicotine was examined for the presence of nicotyrine by means of t h e diazo reaction (47). Distillates from control urines gave a positive diazo reac-
-
amount calculated to be equal to about 9% of the administered nicotine. Also the individual organs of guinea pigs and 3-Butylpyridine bMethylamino-34Amino-a-p yridine rats gave intensified diazo reactions pyridine butyric acid butyric acid following injection of nicotine. From this the conclusion was reached that nicotyrine may be a product of nicotine metabolism. \ CH-COOH This thesis has been explored in this laboratory on the following basis: The /\ AH8 urinary product of nicotine metabolism H CHa in the dog that yields a red color when 2-Methylamino2-Amino-3-pyridine Nicotyrine reacted with cyanogen bromide, appears 3-pyridine acetic acid t o be a product of cleavage of the pyracetic acid rolidine ring of the nicotine molecule. If nicotyrine is an intermediate in nicoFigure 1, Structural Formulas of Pyridine Derivatives tine metabolism, its formation would precede the ring cleavage. However, nitrogen and the two position, did not yield a red color when readministration of nicotyrine did not result in the presence in the acted with cyanogen bromide. 3-(l-Methylaminobuty1)pyridine urine of a compound yielding a red color when reacted with and 3-(1-aminobutyl)pyridine, representative of products of cleavcyanogen bromide (87‘). Unless detoxication of nicotine in the age of the pyrrolidine ring between the nitrogen and the five dog proceeds along more than one path, this result casts doubt position, did yield a red color with cyanogen bromide, but %butylon nicotyrine as a nicotine metabolite, a t least in the dog. pyridine did not. It therefore appears that nicotine derivatives Rate of Detoxication of Nicotine. Using the term detoxicathat produce a red color when reacted with cyanogen bromide are tion in the broad sense of freeing the body of the toxic effects of limited to primary and secondary amines having the nitrogen subnicotine by any and all means, the following findings have been stituted on the carbon alpha to the pyridine ring. The nicotine made: metabolite producing a red color with cyanogen bromide would Many investigators have noted that nicotine is quite rapidly then represent a product of cleavage of the pyrrolidine ring bedetoxified by the animal body in that, given fractionally over a tween the nitrogen and the five position. since the product is period of hours, several times the single lethal dose can be adnot extractable with ether from alkaline urine, this is suggestive ministered without fatal consequences (6,8,19, $3, 39, 40, 43). of a carboxyl group at the end of the resulting side chain. ConThe relative rate of detoxication of nicotine by several species has
@A
0-0 Q-i;;cooH
282
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
b F n studied by comparing the LDWvalues (dose killing 50% of animals), as determined by instantaneous intravenous injection of the total dose, with the lethal dose when given over an 8-hour period by continuous intravenous infusion (26). LDbovalues were: dog, 5 mg. per kg., cat 2.0, rabbit 9.4, and mouse 7.1. Lethal doses over the 8-hour period were: dog, 15 mg. per kg., cat 22, rabbit 40, and mouse 40. These results, while comparative, do not represent the maximum rate of detoxication of nicotine by these animala, since the body concentration of nicotine was built up gradually during the infusion. The results do indicate that nicotine is quite rapidly detoxified by the animal body and that considerable species variation exists in this regard. Recently, further information has been gained for the mouse and the rat through the use of nicotine randomly labeled with C14 (17). At about 2 mg. per kg. dose levels, the mouse eliminated 50% of the administered activity in the urine in 6 hours, and the rat eliminated about 40% in 3 hours, about 85% in 6 hours, and all or almost all in 16 hours. Thus it appears that neither nicotine nor ita products of metabolism are retained by the body. Comparable data for man are not available. However, the following Qtudymade on subjects smoking 20 cigarettes in 7 hours indicates quite rapid detoxication of nicotine by man (61).Control blood, drawn 8 t o 10 hours after smoking, contained nicotine or nicotinelike substances in amounts equal to 0.02 to 0.35 mg. per liter. At the end of the smoking period this was elevated by 0 to 0.13 mg. per liter. Assuming about 60 mg. of nicotine were absorbed from smoking the 20 cigarettes, the authors estimate that 80 t o 95% was detoxified during the smoking period. The analytical method for nicotine used in these studies was a spectrophotometric one. Only one significant study has been made on the effect of development of tolerance on the rate of detoxication of nicotine (49). The study was made on rats given nicotine over a period of 4 to 6 months. Tissue slices prepared at the end of this time showed no change in the capacity of the liver t o detoxify nicotine but that of the kidney and lung was about double that of the same organs from control rats. It is concluded that increased detoxication capacity for nicotine, developed through its chronic administration, is limited, at least in the rat. Nature and Action of Tobacco Smoke Irritants
Discussion of this subject is limited to general principles and certain noncontroversial details. The problem of measurement of tobacco smoke irritation is a most difficult one. Obviously, biological manifestations of irritation must be used and quantitated as best possible. However, the various manifestations are not necessarily interdependent. I n consequence, depending on the chemical nature of the irritant, one manifestation of irritation may be affected to a much greater extent than another. Since tobacco smoke is a very complex mixture of substances which can be varied through changes in the composition of the tobacco smoked, it is apparent that no single biological manifestation of irritation can be used as a complete reliable criterion for evaluating its total irritating potency. This does not mean that the various methods proposed for measuring irritation are of no value, but rather that the significance of each must be carefully interpreted and an 6ver-all picture should not be drawn from results obtained by any one method. Workers in this field have in general sought to develop objective methods for measuring tobacco smoke irritation based on such criteria as erythema and edema, permeability changes, increase in salivary flow, etc. ( l a , 24, SS, 4.2). However, it has become apparent that not all the irritants in tobacco smoke can be properly evaluated by these criteria. Two cigarettes of different composition may yield smoke of equal potency as regards edema production and yet differ drastically in the production of subjective sensations of irritation. The chief cause for this discrepancy lies in the smoke bases, notably nicotine. The free-base nicotine has long been recognized as being subjectively extremely irritating t o the throat (2, 7, 4 1 ) . The degree of this in relation to some of the other tobacco smoke constituents is illustrated by the following experiment (unpublished) :
Vol. 44, No. 2
Table II. Approximate Concentration of Certain Cigarette Smoke Constituents and Their Median Threshold Concentrations for Producing Subjective Sensations of Throat Irritation Median Threshold Concn. Producing Irritation, Mg./L. 0.027 0.7 0.20 6.7 0.35 (formic) 0.34 (acetic) a Calculated as acetic acid: formic and acetic acids make up over 90% of the acids in cigarette smoke. Substance Nicotine Ammonia Volatile acid@
Approx. Conon. i n Cigarette Smoke, Mg./L. 7.1
Atmospheres containing varying amounts of nicotine, ammonia, formic acid, or acetic acid were produced by bubbling air a t known rates through the pure liquid chemicals or water solutions of them, the vapor so generated being led into a mixing chamber where it could be diluted as required by air which had been bubbled through water. The threshold concentration a t which subjective irritation was detected was determined by having subjects make single normal oral inspirations through a tube connecting with the chamber. Twelve to fourteen subjects mere tested with each substance. The results, summarized in Table 11, show that while the content of each of these constituents in cigarette smoke exceedsthe median concentration for the production of subjective sensations of throat irritation, this is outstandingly true for nicotine. Fortunately, salts of nicotine are relatively nonirritating as compared with the free base. This appears to be, in large measure, the basis for the thesis announced by Faitelowitz (10) in 1930, that the greater the acidity of the tobacco the milder the smoke and the greater the alkalinity the harsher the smoke and that determination of the limiting values (acidity/alkalinity) within which a cigarette can be called mild is important, in that it will enable the control chemist to formulate a blend which will lie within these limits. This study clearly points out that very small amounts of free bases contained in smoke produce a scratching effect on the throat and that irritation of the respiratory organs increases as the amount of free bases in the smoke increases. As far as the biologic literature is concerned, this thesis seems to have been largely disregarded. We are, however, convinced that Fait elowitz enunciated a principle of outstanding importance in minimizing cigarette smoke irritation. There undoubtedly exists an optimum balance for cigarette smoke, to be achieved by proper blending of so-called acid and alkaline tobaccos. However, the absolute amounts of acid and alkaline constituents are also of importance in this connection. Thus smoke from a blend of strongly “acid” and strongly “alkaline” tobaccos may be expected to be more irritating than a blend from mildly “acid” and mildly “alkaline” tobaccos. Turning t o a consideration of the significance of using the experimental production of edema by cigarette smoke as a criterion of its irritation, the following observations may be made: The mucous membranes of the rabbit eye are usually used as the test site. The smoke is applied either by directly impinging it on the eye or by dropping in water solutions containing the soluble ingredients of smoke. It has not been shown that it is possible to produce as intense edema production with smoke solutions as by direct application of the smoke. It seems likely that unstable irritants in cigarette smoke may undergo chemical change during the time required t o prepare a smoke solution for use and hence the direct application of the smoke would appear t o be the more valid procedure. Edema production is not influenced by the nicotine content of the smoke and edema does not result from acute application of water solutions of nicotine (14). It is unlikely that other smoke bases are involved. The production of edema is probably a result of the complex mixture of acids, aldehydes, and other classes of compounds in tobacco smoke. Biological data on the absolute and relative edema-producing potencies of a considerable number of organic acids, aldehydes, alcohols, and ketones are available (25). However, evaluation of their possible roles in edema production by tobacco smoke awaits additional data from the chemist on their concentrations in smoke.
INDUSTRIAL AND ENGINEERING CHEMISTRY
February 1952
Much mention has been made in the literature concerning the irritating potency of sc-called “tobacco tars.” Actually, the irritating potency of these materials depends on their method of collection and treatment prior t o testing. Any acute subjective or objective manifestations of irritation produced by them result from the inclusion of water-soluble substances; washed free of these, no such manifestations will be evoked. Pertinent t o the problem of cigarette smoke irritation is the fact t h a t tobacco smoke is a very unstable aerosol. This has an important bearing on the methods for evaluating irritation of whole smoke. Any appreciable delay-that is, 30 seconds-between drawing the smoke and impinging it on the test tissue definitely increases the degree of subjective irritation produced, probably.due t o increasing particle size, and decreases its edemaproducing potency (unpublished observations). Finally, mention should be made of the influence of the moisture content of the tobacco on the irritating properties of the smoke. Probably almost all smokers have experienced that dry tobacco produces a subjectively more irritating smoke. Furthermore, smoke from dry tobacco has a greater edema-producing potency (13). literature Cited (1) Biebl, M., Essex, H. E., and Mann, F. C., A m . J . Physiol., 100, 167 (1932). (2) Biederbeck, J., Inaugural Dissertation, Wurzburg, F. Staudenraus (1908). (3) Corcoran, A.’C., Helmer, 0. M., and Page, I. H., J. Biol. Chem., 129, 89 (1939). (4) Covello, M., Boll. SOC. ilal. bwl. sper., 24, 224 (1939). (5) Dingemanse. E.,and Freud, J., Acta Brevia Neerland. Phusiol.. . Pharrnacol., Microbiol., 3, 49 (1933). (6) Dobrzanski, A., Compt. rend. SOC.biol., 95,83 (1926). (7) Dworzak and Heinrich, described in Hare, H. A., Fiske Fund Prize Dissertation, 1885. (8) Eddy, N. B., and Hatcher, R. A., J . Pharmacol. Ezptl. Therap., 33,295 (1928). (9) Emanuel, W., 2. Kinderheilk., 52,41 (1931). (10)Faitelowitz, A.. 2. Untersuch. Lebensm., 60, 518 (1930). (11) Field, H.. Jr., FOB, P. P., and Fo5, N. L., Arch. Biochem., 9, 45 (1946). (12)Finnegan, J. K., Fordham, D., Larson, P. S., and Haag, H. B., J . Pharmacol. Exptl. Therap., 89, 115 (1947). (13)Finnegan, J. K.,Larson, P. S., and Haag, H. E., Zbid., 91, 357 (1947). (14) Finnegan, J. K., Larson, P. S., and Haag, H. E., Proc. SOC. Exptl. Biol. Med., 65,200 (1947). (16) Fleig, C., and de Visme, P., Compt. rend. soc. biol., 63, 628 (1907). (16) Fretwurst, F.,and Hertz, A., 2. klin. Med., 122, 641 (1932). (17) Ganz, A., Kelsey, F. E., and Geiling, E. M. K., J . Pharmacol. Exptl. Therap., 103, 209 (1951).
w
STEAM COILS AND CIRCULATING FANS
I
F TOBACCO I N
FIRST
SECOND
THIRD
DRY I NG
DRYING
DRYING
STAGE
STAGE
STAG E
8, I
(18) Haag, H.B., and Larson, P. S., Ibid., 76,235 (1942). (19) Haag, H.B.,Larson, P. S., and Finnegan, J. K., Ibid., 85, 356 (1945). (20) Harris, L. J., and Raymond, W. D., Biochem. J . , 33, 2037 (1939). (21) Hatoher, R. A., and Crosby, H., J. Pharrnacol. Exptl. Therap., 32, 1 (1928). (22)Helmer, 0.M., Kohlstaedt, K. G., and Page, 1. H., A m . Heart J . , 17,.15 (1939). (23) Heubner, W., and Papierkowski, J., Arch. Exptl. Path. Pharmakol., 188,605 (1938). (24) Holck, H.G.O., and Carlson, A. J., Proc. SOC.Exptl. Biol. Med., 36. 302 (1937). (25) Lars&, P.‘ S., Finnegan, J. K., and Haag, H. E., Federation Proc., 8 , 312 (1949). (26) Larson, P. S.,Finnegan, J. K., and Haag, H. E., J . Pharmacol. Ezptl. Therap., 95,506 (1949). (27) Larson, P. S.,-Finnegan, J. K., Van Slyke, C. B., and Haag, H. E., Arch. intern. pharmacodynamie, 83, 191 (1950). (28)Larson, P. S.,and Haag, H. B., J. Pharmacol. Exptl. Therap., 76,240 (1942). (29)Larson, P. S., Haag, H. B., and Finnegan, J. K., Zbid., 86, 239 ( 1946). (30)Lautenbach, B. F., Phila. Med. Times, 7,387 (1876-77). (31) Linneweh, W., and Reinwein, H., Z . physiol. Chem., 209, 110 (1932). (32) Melni&, D., Robinson, W. D., and Field, H., Jr., J . Biol. Chem., 136,131, 157 (1940). (33) Mulinos, M. G., and Osborne, R. L., Proc. SOC.EzptZ. Biol. Med.. 32. 241 11934). (34) Nagy, L., Ber. ges. Physiol., 81, 562 (1934);Pharm. Zentralhalle, 7 5 , 737 (1934). (35) Okamoto, T.,Japan. J . Med. Sci., Pharmacol., 3 (103)(1929). (36) Perlmann, H. H., Dannenberg, A. M., and Sokoloff, N., J . A m . Med. Assoc.. 120, 1003 (1942). (37)Perlzweig, W. A.,Levy, E. D., and Starett, H. P., J . Biol.Chem., 136, 729 (1940). (38) Schulmann, E., and Egret, M. T., Compt. rend. soc. biol., 80,846 (1917). (39) Straub, W., and Amann, A., Arch. Exptl. Path. Pharmakol., 194, 429 (1940). (40) Travell, J., Bodansky, O., and Gold, H., J. Pharmacol. Ezptl. Therap., 69,307 (1940). (41)Vandencorput, E., A m . J . Med. Sci., 23, 522 (1852). (42)Weatherby, J. H., J . Lab. Clin. Med., 25, 1199 (1939-40). (43) Weatherby, J. H., Proc. SOC.Exptl. Bwl. Med., 42, 593 (1939). (44) Werle, E.,Biochem. Z . , 298, 268 (1938). (45)Werle, E.,and Becker, H. W., Ibid., 313, 182 (1942). (46)Werle, E., and Koebke, K., Justus LiebiQs Ann. Chem., 562,60 (1949). (47) Werle, E.,Koebke, K., and Meyer, A., Biochem. Z.,320, 189 (1950). (48)Werle, E., and Miiller, M., Zbid., 308, 356 (1941). (49) W,erle, E., and Uschold, E.,Ibid., 318, 531 (1948). (50) Wolff, W. A.,and Giles, W. E., Federation Proc., 9,248 (1960). (51)Wolff, W. A.,Hawkins, M. A., and Giles, W. E., J. Pharmaeol. Exptl. Therap., 95, 145 (1949). R E C ~ I V EAugust D 8 , 1951.
AIR
STEAM SPRAYS AND
COOL I NG
REORDERING
CHAMBER
’
CHAMBER
8, I
STEAM COILS AND C IRCULAT ING FANS
283
I
iNLET AIR
STEAM SPRA~S AND CIRCULATING FANS
Diagram of Drying and Reordering Unit (See Darkis and Hackney, Page 284)
.
