344 



SCIENCE. 



[N. S. Vol. XV. No. 374. 



author's previous work in the light of re- 

 cent discoveries, and maintained that vital 

 phenomena, in general, are caused by the 

 electrical charges of ions. 



The Nature of Nerve Stimulation, and 

 Alterations of Irritahilit]) : Professor 

 Ai-iBEBT P. IMathews, University of Chi- 

 cago. 



The irritability of nerve protoplasm 

 varies inversely with the stability of the 

 hydrosol state of its colloids. Stimulation 

 is gelation, and is brought about by nega- 

 tive electx'ical charges. Chemical stimula- 

 tion is really an electrical stimulation due 

 to the charges which the ions bear. Nega- 

 tive charges stimulate, positive charges pre- 

 vent stimulation. The nerve impulse is 

 due to a progressive precipitation of col- 

 loids by negative charges, the negative 

 charges being regenerated by the precipita- 

 tion of each succeeding mass of colloids. 

 The negative variation, in other words, 

 stimulates each successive segment of the 

 nerve, and is regenerated by the change it 

 produces in the colloids. AnsEsthetics pre- 

 vent precipitation. It is not the valence, 

 in ultimate analysis, which produces stimu- 

 lation, but the movement of the charge, 

 chemical stimulation being thus identical 

 with stimulation by light. 



The Effect of Potassium Cyanide and Lack 

 of Oxygen on the Fertilized Eggs of the 

 Sea-urchin, Arhacia: Professor E. P. 

 Lyon, University of Chicago. 

 During each cleavage of the egg (tested 

 to the third), there is a period of slight re- 

 sistance to potassium cyanide and to lack 

 of oxygen, followed by a period of much 

 greater resistance. The period of least re- 

 sistance comes about ten minutes after fer- 

 tilization, and almost immediately after 

 each succeeding cleavage. 



Experiments with Zygadenus venenosus: 

 Professor Reid Hunt, Johns Hopkins. 

 The author has made a chemical and 



physiological study of this poisonous plant. 

 He has isolated an alkaloid or a mixture of 

 alkaloids having most of the chemical and 

 physiological characteristics of veratrine. 



Demonstration of the Glands in the Oviduct 

 of the Fowl: Professor A. R. Cushnt, 

 University of Michigan. 

 Four varieties of glands have been 

 found, secreting, respectively, albumen, the 

 soft membrane, the hard shell, and, appar- 

 ently, mucus. The last variety has been 

 hitherto undesci'ibed. They are interposed 

 between those secreting albumen and those 

 secreting the soft membrane. 



An Attempt to Obtain Regeneration of the 

 Spinal Cord : Dr. Percy M. Dawson and 

 Edwin N. Riggins, Johns Hopkins. 

 The animal, a young bitch, was nursed 

 \vith the greatest care for one hundred and 

 twelve days after the operation. Although 

 the healing was per primum, with very lit- 

 tle formation of scar-tissue, there was never 

 any conclusive clinical evidence of con- 

 scious sensation, or of voluntary motion in 

 the parts of the body supplied by the cord 

 posterior to the section. 



T/ie Formula for Determining the Weight 

 of the Central Nervous System in Frogs 

 of Different Sizes: Professor H. H. 

 Donaldson, University of Chicago. 

 It was shown that in the case of the bull- 

 frog and leopard frog, the weight of the 

 central nervous system (brain and spinal 

 cord) was a function of the body- weight 

 and length of the frog, combined. 



If the weight of the central nervous system (in 



milligrams ) = F ; 

 length of the entire frog (in millimeters ) = 7y ; 

 weight of the body (in grams )^W; 

 and the constant coefficient^ (7; 

 then: 



Ni (^Ziog w) a 



In the case of the bull-frog 0=30. 



In the case of the leopard-frog (/=27.6. 



