422 



SCIENCE. 



[N. S. Vol. XXII. No. 562. 



great destruction of proteids that imme- 

 diately precedes death. 



That the problem of diabetes mellitus, 

 though still unsolved, has received light 

 from many sides through pharmacological 

 investigations, I need hardly state. I will 

 merely remind you that the discovery of 

 phlorhizin diabetes showed us a hitherto 

 unknown capacity of the kidney to secrete 

 sugar, that the work of Lusk and his asso- 

 ciates led to the establishment of a definite 

 ratio between nitrogen and dextrose excre- 

 tion in diabetes, and that Blum and Herter 

 found an adrenalin glycosuria which may 

 perhaps throw some light on the puzzling 

 nervous forms of diabetes. 



Again, through poisoning by phosphorus 

 and arsenic the relation of lactic and the 

 amido-acids to the intermediary metabo- 

 lism was first shown, while as regards the 

 more intimate metabolic processes and their 

 relation to ferment action, the toxicological 

 experiments of Jacobi and of "Wakeman 

 have brought us important light. Through 

 poisoning by chloral, by camphor and ni- 

 trotoluol, the discovery of glycuronic acid 

 was made, the normal occurrence of which 

 in the organism was only later established. 

 Indeed, the various chemical reactions of 

 the organism, of which we have examples 

 in the formation of hippuric acid in the 

 kidneys, in sulphocyanide, in methylation, 

 in oxidation and reduction, were all of 

 them first discovered through the action of 

 chemical or pharmacological agents. Fur- 

 thermore, as regards the location and in- 

 tensity of these processes, the investiga- 

 tions of Ehrlich and of Herter have given 

 us definite information. I would like to 

 refer here to an interesting observation 

 from Herter 's studies which demonstrates 

 with special clearness to the eye the oxygen 

 requirements of the muscles and shows 

 with what energy the muscles appropriate 

 oxygen not only from oxyhemoglobin, but 

 also from other reducible substances. Her- 



ter found that if animals receive intra- 

 venous infusions of methylene blue the 

 pectoral muscles were soon colored deep 

 blue, but that if during the experiment the 

 access of oxygen was hindered by giving 

 the animals air mixed with carbon mon- 

 oxid, the blue muscles in a few seconds 

 recovered their natural red color ; they had 

 almost momentarily reduced the methylene 

 blue to the colorless leucobase. It is also 

 known that through the action of hydro- 

 cyanic acid the capacity of the organs to 

 take up oxygen from the blood is much re- 

 duced or destroyed. This process also it 

 was possible to render easily visible by the 

 method of methylene blue infusion. As 

 we, have seen, the pharmacological method 

 has revealed to us a series of functional 

 characters of the organism; but its biolog- 

 ical significance appears to extend even 

 further. It seems possible with such 

 methods, if only gradually, to reach a more 

 intimate knowledge of the chemical con- 

 stitution of protoplasm, and finally, per- 

 haps, to arrive at an insight into the chem- 

 ical interpretation of its functions. If, 

 under the influence of a pharmacological 

 agent, we observe an immediate essential 

 alteration in the function of a cell, we have 

 to assume that a chemical change has oc- 

 curred in its vital center— in what Ehrlich 

 has called the ' Leistungskern, ' that is, the 

 chemical center of vital activity. On the 

 other hand, if we have before us a gradu- 

 ally developing alteration, this may have 

 been called forth in a secondary manner, 

 through chemical changes in the reserve 

 material or in the supporting elements of 

 the cells, perhaps in the groups of atoms 

 which we conceive as side-chains. Given 

 a knowledge of the constitution and the 

 chemical mode of action of agents operating 

 as acute intoxicants, we should also be able 

 to reach conclusions as to the chemistry 

 of their point of attack, that is to say, re- 

 garding that substratum of the living sub- 



