374 LAY SERMONS, ADDRESSES, AND REVIEWS. [xv. 



if possible, to devise some means of staying the plague. 

 In reading the Report 1 made by M. de Quatrefages in 

 1859, it is exceedingly interesting to observe that his 

 elaborate study of the Pebrine forced the conviction 

 upon his mind that, in its mode of occurrence and prop- 

 agation, the disease of the silkworm is, in every respect, 

 comparable to the cholera among mankind. But it 

 differs from the cholera, and so far is a more formidable 

 disease, in being hereditary, and in being, under some 

 circumstances, contagious as well as infectious. 



The Italian naturalist, Filippi, discovered, in the 

 blood of the silkworms affected by this strange disease, 

 a multitude of cylindrical corpuscles, each about 6 ^ th 

 of an inch long. These have been carefully studied by 

 Lebert, and named by him Panliistophyton / for the 

 reason that, in subjects in which the disease is strongly 

 developed, the corpuscles swarm in every tissue and 

 organ of the body, and even pass into the undeveloped 

 eggs of the female moth. But are these corpuscles 

 causes, or mere concomitants, of the disease? Some 

 naturalists took one view and some another ; and it was 

 not until the French Government, alarmed by the con- 

 tinued ravages of the malady, and the inefficiency of 

 the remedies which had been suggested, dispatched M. 

 Pasteur to study it, that the question received its final 

 settlement ; at a great sacrifice, not only of the time 

 and peace of mind of that eminent philosopher, but, I 

 regret to have to add, of his health. 



But the sacrifice has not been in vain. It is now 

 certain that this devastating, cholera-like Pebrine is 

 the effect of the growth and multiplication of the Pan- 

 histophyfon in the silkworm. It is contagious and in- 

 fectious because the corpuscles of the ParJiistopliyton 

 pass away from the bodies of the diseased caterpillars, 



'Etudes sur lea Maladies A.ctuelles des Vers a" Soie, p. 53. 



