BROWN-SEQUARDS EXPERIMENTS 235 



Jan. 15, 1896). Moreover, Voisin and Peron have found evidence 

 that in epilepsy a toxin is produced which causes convulsions 

 when injected into animals (see Archives de Neurologie, xxiv., 

 1892, and xxv., 1893, and Voisin's L'Epilcpsie, Paris, 1897, pp. 125- 

 133). It is thus not a mere speculation to suppose that a toxin 

 was produced in the guinea-pig epilepsy, and that this affected the 

 germ-cells of both sexes. This suggestion is made by Prof. Bergson 

 in his remarkable book L' Evolution Creatrice (1907), and he adds 

 to the suggestion the query, May not something of the same sort 

 be true in those cases where acquired peculiarities are transmitted ? 



Prof. T. H. Morgan (1903, p. 255) also notes an interesting 

 fact. " While carrying out some experiments in telegony with mice, 

 I found in one litter of mice that when the young came out of the 

 nest they were tail-less. The same thing happened again when the 

 second litter was produced, but this time I made my observations 

 sooner, and examined the young mice immediately after birth. I 

 found that the mother had bitten off, and presumably eaten, the 

 tails of her offspring at the time of birth. Had I been carrying on 

 a series of experiments to see if, when the tails of the parents were 

 cut off, the young inherited the defect, I might have been led into 

 the error of supposing that I had found such a case in these mice. 

 If this idiosyncrasy of the mother had reappeared in any of her 

 descendants, the tails might have disappeared in succeeding genera- 

 tions. This perversion of the maternal instincts is not difficult to 

 understand, when we recall that the female mouse bites off the 

 navel-string of each of her young as they are born, and at the same 

 time eats the after-birth. Her instinct was carried further in this 

 case, and the projecting tail was also removed. 



"Is it not possible that something of this sort took place in 

 Brown-Sequard's experiment ? The fact that the adults had eaten 

 off their own feet might be brought forward to indicate the possi- 

 bility of a perverted instinct in this case also." On the other hand, 

 this interpretation cannot apply to some other results which Brown- 

 Sequard observed. 



Sommer's Experiments far from corroborating Broivn-Seqnard's. — 

 In experiments the results of which were published in 1900, Max 

 Sommer repeated some of those which Brown-Sequard and others 

 had made, but without corroborating them. 



The so-called " epilepsy " was induced by cutting the sciatic nerve 

 on one side or on both sides ; the tendency to " fits " occurred some 



