STATE HORTICULTURAL SOCIETY. 35 



eating their unliealthy eondition. Next, to test the possibility of 

 infection by exposing healthy wornis to those already suffering from 

 the disease. Pasteur })hieed twt'uty-tive ]ierf(M'tly sound s])ecimeiis with 

 twenty-tive others which had inherited the disease from unhealthy 

 ancestors. He also set aside another lot of twenty-five, identical with 

 those exposed to the contagion, as a check lot. All the latter trans- 

 formed without accident, in due season, every specimen coming 

 through in j)erfect health. Of those exposed to the infection, two 

 died on the lUth, two nu)re on the 18th, one on the 2()th. nine on the 

 21st, five on the 22d. and four on the 28d of May. Then, after a 

 brief interval, another died on the 2i)t]\: five on the 29th, and again 

 five on the ;]Oth. six on the 81st, tAvo (m the 2d of June, and one on 

 the 8d, at which time only two remained alive, and these finally 

 transformed to chrysalids. Of the second twenty-five luingled with 

 these, the victims (jf the hereditary transmission of flaeherie, not one 

 transformed, l)ut all ])erished of the disease. It is clear fTom these 

 experiments that flaeherie is directly contagious, and that it may be 

 conveyed artificially by the use of material obtained from unhealthy 

 worms. The fact should also be mentioned, that in every case where 

 worms died from this disease, Pasteur found the characteristic bac- 

 terial forms in the intestines, with the exception of two which died 

 the day following the treatment of their food with dust from the 

 infected hatchery. In this case it is probable that the mechanical 

 irritation or poisonous chemical character of the material used had 

 something to do with the fatal effect. Other experiments of Pasteur 

 tended to show that flaeherie might be produced by treating the 

 food of healthy worms with the fermenting infusion of mulberry 

 leaves alone, in which it is presumed that only the ordinary bacteria 

 of fermentation and })utref action actually occurred. He leaves us in 

 doubt, however, whether these fluids might not also have become 

 accidentally infected with the characteristic Micrococcas bomhijch of 

 the silk-worm disease, and I have myself little doubt that this was 

 the case, since I have found it very difficult to keep fermentable 

 fluids free frcmi these bacteria, if exposed where liable to infection. 



There is also some grouiul for believing that flaeherie is some- 

 times spontaneous, arising where the worms are too much crowded, 

 where the cpiality of the food is inferior, and where the ventilation 

 of the breeding houses is poor. As it is. however, practically impos- 

 sible to say that worms suffering from it under such circumstances 

 have not been exposed to this subtle contagion, which may easily have 

 been wafted to them on any breeze, it must remain doubtful whether 

 such unfavoral)le conditions can really originate the disease de novo, 

 or whether they merely stimulate the development of the offending 

 bacteria by reducing the vitality of the larvae. 



I think that the above must satisfy you that flaeherie or schlaff- 

 sucht of the silk-irorni is a contagious disease; that the contagion 

 may be artificially communicated with success to healthy worms; 



