OcTOBfcR 6, 1905.] 



SCIENCE, 



421 



glandular stimulants gave rise to an in- 

 creased accumulation. And, indeed, he 

 found that when fishes were repeatedly 

 injected with pilocarpine, the content of 

 the swimming bladder in oxygen gas was 

 distinctly greater than in the case of the 

 gas from the normal fishes, which permits 

 the conclusion that the epithelia of the 

 swimming bladder liberate a gas in a man- 

 ner analogous to the liberation of secretions 

 from true glands, and further that these 

 epithelia are not penetrable in either direc- 

 tion like a diffusing membrane. 



Another fact deserves brief notice in this 

 relation. It is the interesting observation 

 of Magnus that when ammonia gas is in- 

 jected into the veins the alveolar epithelium 

 of the lungs is not penetrable, since no 

 trace of ammonia can be detected in the 

 expired air, whereas after the inhalation 

 of ammonia the gas penetrates readily into 

 the blood through these same epithelial 

 cells. This is merely one striking example 

 of the many known cases in which animal 

 epithelial membranes are penetrable in one 

 direction for certain substances like water, 

 salts or urea, while opposing strong resist- 

 ance to the passage of these in the opposite 

 direction. The mechanism of this regula- 

 tory arrangement has not yet been cleared 

 up and further progress seems hardly pos- 

 sible without the aid of pharmacological 

 methods. 



To enter upon the physiology of the 

 heart at this time would carry us too far. 

 Pharmacological facts which have proved 

 of importance in giving us our present 

 knowledge are doubtless sufficiently known 

 to you. We may say, however, that even 

 in regard to the recent controversy over 

 the myogenic and neurogenic theories of 

 the cardiac motions and over the general 

 character of the heart muscle, the sys- 

 tematic study of the cardiac poisons has 

 contributed much that is important and, as 



Harnack has indicated, may perhaps fur- 

 nish the final decision. 



Permit me now to direct your attention, 

 for a few moments, to some of the physi- 

 ologico-chemical results of pharmacological 

 investigations. It lies in the nature of 

 things that the results should be numerous 

 in a field that has to do solely with the 

 chemical inter-relations between the phar- 

 macological agent and the living organism. 

 I shall not tire you with an enumeration 

 of facts already well known. I shall refer 

 only to a few of the more significant bio- 

 logical reactions which we owe to pharma- 

 cological investigation. The study of 

 poisoning by acids led to the discovery of 

 ammonia-production in the organism, and 

 this in turn to the Schroeder experiments, 

 which positively demonstrated the produc- 

 tion of urea in the liver. Pharmacological 

 methods have also contributed materially 

 to the elucidation of numerous other im- 

 portant problems in metabolism. One of 

 the most actively discussed problems has 

 been the question whether sugar can arise 

 from proteid, and this question has been 

 definitely answered, as it seems to me, by 

 the experiments of Kolly. This observer 

 conducted experiments on animals which 

 had been rendered giycogen-free by means 

 of fasting and strychnine spasms. He 

 then brought about an increased destruc- 

 tion of proteids by means of fever, induced 

 through the action of bacteria and toxines 

 and was able to demonstrate that there 

 occurred a new production of glycogen 

 under these circumstances in the liver and 

 in the muscles. As the fat-reserve of the 

 animals had already sunk to a minimum 

 during the period of fasting, it is clear that 

 the source of the newly formed glycogen 

 is to be sought in the increased destruction 

 of proteids in the organism. The same 

 sequence of events was demonstrated by 

 Roily in fasting rabbits at the time of the 



