66 PARASITES OF MAN 



have had access to the work in which Lewis's experiments were 

 originally recorded, and to which, therefore, I must call their 

 attention. Thus, Dr Tommasi has fallen into the error of 

 supposing that the investigations of Lewis were made in England. 

 It is of very little moment where the experiments were carried 

 on, but Tommasi's statement (appendix, loc. cit., p. 161), 

 wherein he says that Pellizzari's experiments, in which he 

 himself took part (ai quali io stesso ho assistito), are even more 

 complete than those made in England by Dr Lewis, and 

 in Germany by Dr Kiichenineister, cannot be allowed to pass 

 unchallenged. If Tommasi had enjoyed the opportunity of 

 consulting Lewis's original memoir, he would not have under- 

 estimated our countryman's labors. The memoir by Lewis 

 is singularly complete, and well-nigh exhausts all the facts 

 that can have any interest in relation to the question of 

 public health. Towards the close of his essay he expressly 

 states, as the result of investigation " (1) That exposure to a 

 temperature of 120 Fahr. for five minutes will not destroy 

 life in Cysticerci, but that they may continue to manifest indica- 

 tions of life for at least two or three days after such exposure ; 

 (2) that exposure to a temperature of 125 Fahr. for five 

 minutes does not kill them ; but (3) after being subjected to 

 a temperature of 130 Fahr. for five minutes, they may be 

 considered to have perished. After exposure to this and higher 

 temperatures, in no instance have I been able (he adds) to 

 satisfy myself that the slightest movements took place in their 

 substance when examined even under a high power. At least, 

 it may be confidently asserted that, after exposure for five 

 minutes to a temperature of 135 to 140 Fahr., life in these 

 parasites may be considered as absolutely extinct" (p. 139). 

 Thus the statements of Lewis and Pellizzari were in perfect 

 accord ; and seeing that their conclusions were alike the result 

 of very careful and independent inquiry, it seemed as if 

 the question at issue was finally solved. These investigations 

 made it perfectly clear that Cysticerci of all kinds, whether 

 found in veal, beef, or pork, could not retain their vitality when 

 exposed to a temperature of 60 Centigrade, or, in other words, 

 140 Fahr. 



The rather severe strictures made on Perroncito's earlier 

 experiments induced the Turin professor to go over the subject 

 more carefully, when he obtained excellent results. He finally 

 ascertained that Cysticerci perished at a temperature below 



