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SCIENCE. 



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



and physical means almost exclusively. 

 The scalpel and scissors, electrical, thermal 

 and mechanical stimuli have long served its 

 purposes. The manifold means of chem- 

 istry have scarcely been utilized. Its ap- 

 pliances and its study belong, indeed, to 

 pharmacology, which is, as an American 

 fellow-worker has tersely said, 'the experi- 

 mental chemistry of protoplasm.' 



The drugs, that is the chemical reagents, 

 penetrate into the interior of the organs 

 and reach parts which are not accessible to 

 the scalpel and the electric current. In- 

 deed, the differential ^action of poisons — 

 that which has to do with single parts of 

 organs or single especial groups of cells — 

 is the important part of the pharmacolog- 

 ical method. But we must concede that it 

 has not attained for the most part the 

 undoubted certainty and clearness of phys- 

 iological methods, for every drug which we 

 wish to use as an instrument of investiga- 

 tion must first itself be investigated, its 

 mode of action first be recognized and de- 

 termined. You all know well how difficult 

 and equivocal such investigations are, and 

 ■ it is easily intelligible that, especially in 

 the beginnings of such investigations, while 

 there was no large array of pharmacolog- 

 ical facts supporting one another, one 

 scarcely ventured from these to draw far- 

 reaching conclusions. 



An interesting example of this sort is the 

 admirable investigation of Felice Fontana 

 on Indian arrow poison, which was carried 

 out more than one hundred years ago. 

 Fontana was forced to the conclusion, 

 through ingenious experiments, which re- 

 sembled the much later ones of Claude 

 Bernard, that the arrow poison paralyzes 

 neither muscle itself nor the whole nerve, 

 but only the endings of the latter and that, 

 indeed, the latter must possess a structure 

 different from the nerves themselves, of 

 which anatomy and physiology took no 

 cognizance. Fontana, however, did not 



dare to draw the right conclusion because 

 the proof was indeed a pharmacological 

 and not an anatomical one. Only much 

 later was it learned that properly con- 

 ducted and correctly interpreted phar- 

 macological experimentation possesses the 

 same power of conviction as any other 

 exact scientific method. And it is pre- 

 cisely the curara poison which has led to 

 positive physiological discoveries. By its 

 help Boehm and Nussbaum, through the 

 discovery of the so-called paradoxical vagus 

 action, discovered the vasopressor nerves 

 and the accelerator fibers in the trunk of 

 the vagus nerve in dogs and cats ; and later, 

 with the help of the same poison, Boehm 

 obtained the proof, otherwise inaccessible 

 to physiology, that the nerve endings in 

 the muscles possess the same capacity for 

 fatigue and recovery as the muscle itself. 

 The important problem of the close con- 

 nection between the irritability and the 

 conductivity of nerves was not soluble ex- 

 cept by the aid of the pharmacological 

 method, that is, the methodical utilization 

 of poisons like curara, veratrin and carbon 

 dioxide. 



Formerly it was impossible to detect any 

 physiological or morphological difference 

 either in the arrangement or in the general 

 structure of centrifugal and centripetal 

 nerve tracts. But the narcosis experiments 

 of Fraser, Alms, Joteyko and especially the 

 more recent ones by Dixon with cocain, 

 showed that they must be chemically dif- 

 ferent from one another, inasmuch as they 

 react differently to poisons. 



Highly important, also, are the physi- 

 ological results which Langley obtained 

 with the help of nicotin poisoning in rela- 

 tion to the sympathetic ganglia. He was 

 able to show that by means of nicotin the 

 sympathetic ganglia, and through them all 

 the preganglionic nerves, were paralyzed, 

 while the post-ganglionic nerves escaped. 

 So it is possible to decide by this means 



