174 The Pebrine Corpuscles in the Silkivorm. 



feeding upon the mulberry leaf. The corpuscles are then found 

 distributed over the surface of the leaf in debris; and a single 

 repast is said to be sufficient to occasion the disease. It is worthy 

 of note that an intestinal lesion is then produced. 



It cannot be doubted that chancres would in like manner result, 

 if, by any natural process, the secretion from similar sores could be 

 applied to the mucous surface of the intestines. But it may well 

 be doubted if this species of infection of the primae rise ever occurs 

 in the human subject. A vacciniculturist of this city, however, 

 once informed the writer that he was in receipt of numerous orders 

 from practitioners of the homoeopathic delusion, who desired to 

 secure an infinitesimal quantity of vaccine virus, inibbed up with 

 sugar of milk for internal administration ! 



2. Pebrine and syj^hilis are alike communicahle by accidental 

 inoculation. Pasteur discovered numerous cicatrices in healthy 

 worms, which resulted from wounds. These wounds were inflicted 

 by booklets attached to the anterior organs of locomotion, in those 

 cater]3illars with which they had come into frequent contact. 

 These were never seen in isolated individuals. He remarks that 

 not infrequently these sharp booklets, by which the caterpillar is 

 enabled to cling to the leaf upon which it feeds, are inserted into 

 the faeces or integument of diseased worms, and subsequently into 

 the bodies of those that are sound, thus serving to propagate the 

 disease by accidental inoculation. It is evident that there is here 

 also the possibility of the production of mediate contamination, the 

 porte-virus (if it be allowable to coin a suggestive word) being 

 exempt from infection. 



3. Pebrine and syphilis alike require a period of incubation, 

 before the phenomena of general disease appear. Pasteur dis- 

 covered that after accidental or artificial inoculation, and also after 

 the ingestion of disease germs, a period of from ten to twelve days 

 elapsed before external manifestations of pebrine appeared. By 

 feeding a number of larves with the solution which has been already 

 referred to, and by killing and carefully examining a fixed number 

 of bodies at consecutive dates, he was enabled to follow the evolu- 

 tion of the disease, and to trace its natural history. In every 

 instance the period of incubation was noted. This is such a con- 

 stant concomitant of contagious diseases, that it may well be 

 considered essential to their full development.* 



4. The first general indications of constitutional disease in 

 pebrine and syphilis appear as infegumenta^'y lesions. In the 

 course of the experiments conducted by Pasteur, whenever a number 

 of larves were selected for inoculation or infection, a similar number 

 of the same age and habitat were set aside in a healthy condition, 

 in order to serve the purposes of comparison. At the exjjiration of 



* See 'Nouv. Diet do Med. et dc Chi. Jaccoud,' art. "Contagion." 



