Maech 28, 1902.] 



SCIENCE. 



493 



trical charges their ions bore. During the 

 summer, and later in a lecture before the 

 Medical Society of the University of Chi- 

 cago, he applied these results to the action 

 of toxines and antitoxines. He was, how- 

 ever, unable to discover any series of facts 

 for the anions similar to those he estab- 

 lished for the kations, and he referred the 

 poisonous action of a pure sodium chloride 

 solution to the monovalent kations the salt 

 possessed instead of to the anions. In his 

 work on muscle, also, the stimulating 

 action of sodium chloride was referred to 

 the sodium ions and I pro-\dsional]y adopted 

 the same explanation in my preliminary 

 paper on the action of salts on nerves pub- 

 lished in the Journal of the Boston Society 

 of Medical Sciences last spring: Professor 

 Loeb's attention was thus draAvn chiefly to 

 the kations. He attributed the undoubt- 

 edly greater stimulating action of the 

 bivalent and trivalent anion sodium salts 

 to their calcium-precipitating properties, 

 having been brought to this conclusion by 

 the peculiar action of fluorine. 



In 1897 Professor Loeb directed my at- 

 tention to physical chemistry, and his 

 results on muscle appeared so remarkable 

 that I began, three years ago, a study 

 of the stimulating action of salts on 

 nerves. The relationships were so complex 

 that a long series of observations were 

 necessary, but, during the spring of 1901, 

 I published a preliminary paper in which, 

 owing to incomplete results, I fell into 

 several errors. The stimulating action of 

 the higher anions was provisionally re- 

 ferred to the hydroxyl ions the solutions 

 generally contained, and the peculiar ac- 

 tivity of sodium compounds to the dif- 

 fusion of Na ions into the muscle. 



Further experiments showed me that 

 certain of the conclusions were wrong. 

 After reading Hardy's paper on ' Colloidal 

 Solutions ' and hearing Professor Loeb 's 

 lecture on the possible importance of the 



valence of ions, and more particularly of 

 the kations, in determining their poisonous 

 character, I had the opportunity of putting 

 together my experiments. After com- 

 puting the degree of hydrolysis and 

 the number of H and OH ions in the 

 solutions, it appeared that it was not the 

 OH ions which were the cause of the 

 stimulating action of the borates and 

 citrates. The resemblance of my results to 

 those of Hardy on colloidal solutions was 

 apparent, and, apart from certain excep- 

 tions left for future investigation, I was led 

 to infer that stimulation was due to the 

 negative ions, and that the positive ions pre- 

 vented stimulation ; and also that as the 

 stimulating action of the anions generally 

 increased with an increase in valency, the 

 stimulation was due to the electrical 

 charges the ions bore. Following out tills 

 idea, which, as mil be seen, was the exten- 

 sion of Loeb's idea of the importance of 

 valence, the electrical relationships of 

 nerves, the nature of stimulation and of 

 changes in irritability and the nature of 

 the nerve impulse appeared in a new light. 

 The main results and conclusions were pre- 

 sented before the Medical Society of this 

 University on December 2. 



Meanwhile, unknown to me. Professor 

 Loeb had begun to doubt that the calcium 

 precipitation by the higher anions was the 

 real cause of their action. Upon hearing 

 my results and conclusions he perceived 

 that they agreed with his facts as well.* It 

 is with gratitude that I acknowledge my 

 indebtedness to Professor Loeb, who 

 showed me in which direction to look and 

 who as a pioneer has opened one of the 

 most fruitful fields of science. My own 

 conclusions supplement and, it seems to 

 me, make more precise those general ideas 

 which were guiding him. 



* Since this paper was sent to the editor, 

 Professor Loeb has published in the February 

 number of the American Journal of Physiology a 

 portion of his results on muscle. 



