Scientific Proceedings. 



149 



hours to rays of the same intensity caused no visible effects on 

 form, rate of division or process of conjugation. 



I have exposed the sperm of the toad to heat at 50° and 65 0 C. 

 for from 15 to 20 minutes. This exposure destroys the fertilizing 

 power of most of the spermatozoa but the few eggs fertilized by 

 such sperm develop normally. Sperm exposed for from 15 to 20 

 minutes to the following solutions: ^ per cent, formol, 12.5 

 per cent, ethyl alcohol, 1 per cent. NaCl, per cent. HC1 and 

 3*2 per cent. KOH, has the power of fertilizing toad eggs. Prac- 

 tically all of the resulting larvae which have been preserved appear 

 normal at the end of one month after fertilization of the eggs. 

 Sperm exposed to stronger solutions of the same substances for 

 15 to 20 minutes seems to lose power of fertilizing. No abnormal 

 larvae have developed from the few eggs thus fertilized. 



The short breeding season of the toads prevented as extended 

 a series of experiments along these lines as had been planned. 



103 (246) 



On the absorption of toxins by the nerves. 



By CYRUS W. FIELD. 



\From the Research Laboratory of the Department -of Health, of 



New York City.] 



In an article published in the Archiv ficr experimentelle Pathol- 

 ogie una 1 Pharmakologie, Vol. 49, Meyer and Ransom stated as a 

 result of their experiments that tetanus toxin enters the central 

 nervous system through the motor nerves, and moreover that it 

 passes to the cord by way of the axis cylinder. Since that time 

 Meyer (1905) has demonstrated that diphtheria toxin after injection 

 into the experimental animal, could be demonstrated in the per- 

 ipheral nerves. In a large number of experimental animals injected 

 with both tetanus and diphtheria toxin, I have been able to show 

 that the toxin could be demonstrated in the peripheral nerves 

 leading from the inoculated area, and by the use of the right dose, 

 and at a certain time, free toxin could be demonstrated in the cord, 

 and yet the other tissues of the body including the blood, liver, 

 spleen and kidneys showed no free toxin. 



