July 1, 1904.] 



SCIENCE. 



-■5 



a good knowledge of elementary organic 

 chemistry is necessary, and it is essential 

 also that one should have some idea of the 

 part played by bacteria in the organism in 

 producing complex aromatic substances 

 from the disintegration of proteins, since 

 the indications here are often of great im- 

 portance. 



And this brings us to consider the second 

 type of relation between chemistry and 

 medicine, a relation which involves the 

 question of organic synthesis or disintegra- 

 tion in the animal body. At an earlier 

 stage in the discussion it was assumed that, 

 Topsy like, things 'just growed that way.' 

 Later the mysterious electricity and still 

 more mysterious vital force were called in 

 to account for everything not easily explic- 

 able by known chemical or physical means. 

 While it is probably true that many of the 

 phenomena of life are and will remain 

 quite beyond our power of explanation, and 

 that here as elsewhere we must accept the 

 ignoramus and ignorahimus of Du Bois 

 Reymond as final, we are coming, on the 

 other hand, to the recognition of the com- 

 parative simplicity of other problems, the 

 solution of which falls within the province 

 of the new physiological chemistry. Medi- 

 cine will be the chief gainer by these in- 

 vestigations. 



It was certainly an auspicious day for 

 chemistry and medicine also when Pasteur 

 developed his biological theory of alcoholic 

 fermentation. Not long after came the 

 work of Kiihne, Briicke and others on the 

 enzymes, already referred to, and finally 

 Buchner to clearly demonstrate the long- 

 suspected enzymic character of the yeast 

 ferment. Practically all recent work in 

 this direction has gone to show that so- 

 called organized fermentations are all de- 

 pendent in turn on enzymic ferments con- 

 tained within the cells. This distinction 

 may probably be made: in the yeast fer- 

 mentations, for example, the sugar to be 



converted is drawn into the cell, and the 

 products, alcohol and carbon dioxide, 

 formed by the zymase, are in turn ex- 

 creted. In diastasic and similar fermenta- 

 tions, on the other hand, certain cells pro- 

 duce an active ferment which is discharged 

 to do its work outside the generating cell. 

 The difference is thus seen to depend on the 

 place where the reaction occurs, which is 

 not a very important point. The ferments 

 are essentially complex chemical sub- 

 stances, able to bring about various reac- 

 tions nearly all of which are of exothermal 

 character. Of the nature of many of these 

 reactions we have pretty accurate Imowl- 

 edge, although of the exact mode of action 

 of the enzyme itself our knowledge is 

 scanty. For the present purpose, however, 

 it is sufficient to recognize that these reac- 

 tions are chemical and we are in a position 

 to trace their bearing on medical problems. 

 The simplest problems of enzyme action 

 we have in the work of some of the so- 

 called digestive ferments. In the changes 

 wrought in starch by the saliva and by one 

 of the pancreatic ferments the chemical ac- 

 tion is one of hydrolysis and very similar 

 to that occurring commonly in the vege- 

 table world. In the germinating seedsj 

 when starch becomes sugar to feed the de- 

 veloping plantlet, water is added through 

 the aid of diastasic ferments, and later, in 

 the ripening of many fruits the same kind 

 of a reaction takes place. These effects, 

 however, are not peculiar to the enzymes; 

 experiment shows that the same starchy 

 substances acted upon by weak acids pass 

 through the same series of changes occur- 

 ring in the body, and even prolonged heat- 

 ing with water has the same general effect. 

 The hydrolytic and purely chemical nature 

 of carbohydrate digestion becomes at once 

 apparent. What happens in the digestion 

 of fats is equally simple. Here, too, hy- 

 drolysis plays the most important part and 

 the work of the lipase enzymes can be 



