172 



SCIENCE 



[N. S. Vol. XLII. No. 1075 



SO powerful that it kills in a few moments 

 large game, such ais the stag or the jaguar. 



Two years ago I was examining a speci- 

 men of this giant among toads when I no- 

 ticed that this creamy secretion made on a 

 scalpel a peculiar, greenish-blue discolora- 

 tion. I at once remembered where I had 

 seen this color years before on a scalpel 

 used in cutting into the medulla of a supra- 

 renal gland. Working from this hint, I was 

 soon able to isolate the now familiar sub- 

 stance, adrenalin or epinephrin, from this 

 toad's glands. Scientists have been not a 

 little surprised to learn that this substance 

 is present in very large amounts in the 

 skin of this tropical toad. It is not found 

 in the skin of the common American toad. 



I also succeeded in isolating the principle 

 to which the toad skin owes its curative 

 power for dropsy, a very dijffierent prin- 

 ciple from epinephrin. It has been ob- 

 tained in the form of beautiful crystals 

 and has the composition represented by 

 the formula, CjsHoiOj, and has been 

 named bufagin. 



Just as in the case of bleeding, we have 

 here another instance of the every-day ob- 

 servation of mankind justified by science. 

 That powdered toad skin could cure dropsy 

 has been ridiculed by the learned for a 

 century, and now we possess in bufagin 

 and in the slightly different bufotalin, 

 which has or'v recently been obtained in 

 crystalline fi rm from the skin of the com- 

 mon European toad, the actual proof of 

 the correctness of the old belief. 



We are now studying the chemical con- 

 stitution of bufagin in my laboratory, and 

 although this problem is one of great difS- 

 culty, we hope, nevertheless, that our work 

 will throw some light on the fundamental 

 chemical properties of cardiac stimulants. 

 We now also understand why the secretion 

 of the skin of Bufo agua may be used as an 

 arrow poison, since it contains these two 



powerful drugs, epinephrin and bufagin, 

 which in overdose act fatally on the heart 

 and blood vessels. 



We can not leave the consideration of 

 this subject without noting the influence 

 that the study of the pharmacological prop- 

 erties of epinephrin has exerted on certain 

 departments of medical science. 



Chromaphilic cells of the body, whether 

 located in the medullary portion of the 

 suprarenal gland, or elsewhere, all yield 

 epinephrin, and modern studies have shown 

 that these chromaphilic cells are intimately 

 related to the sympathetic nervous system 

 in their origin, and have differentiated 

 themselves from it. We are not surprised, 

 therefore, to find that epinephrin, the se- 

 cretory product of these cells, has an elec- 

 tive affinity for the sympathetic nervous 

 system, the thoracico-abdominal part of 

 the autonomic system. The well-known 

 symptoms that follow upon the administra- 

 tion of epinephrin, extreme vaso-constrie- 

 tion, tachycardia, dilatation of the pupil, 

 inhibition of peristaltic movement in the 

 alimentary canal, contraction of the pyloric 

 and ileo-cecal sphincters, increased motil- 

 ity of the pregnant uterus and glycosuria 

 have all been shown to be due to the fact 

 that this hormone stimulates and sensitizes 

 the sympathetic myoneural and adenoneu- 

 ral junctions or terminations of the sympa- 

 thetic nervous system. Numerous experi- 

 ments have shown that the changes induced 

 by epinephrin in the activity of various or- 

 gans which are innervated by the sympa- 

 thetic nervous system are in all respects 

 like those that are brought about by elec- 

 trical stimulation of this system, and it is 

 apparent that such experiments have al- 

 ready assisted in elucidating many obscure 

 points in the functional activity of this 

 part of the nervous system. 



Other interesting observations which 

 deal with the action of this principle upon 



