1880.] On some Points in the Pathology of Antler ax. 559 



cessive artificial cultivations, and the evidence upon which the con- 

 clusion is based. 



The experiments were performed in a very simple manner. The 

 cultivating fluid employed was aqueous humour, the animals inoculated 

 Were chiefly mice, though guinea-pigs, rabbits, cows, and on one 

 occasion a sheep were also used. But mice, being especially suscep- 

 tible to the poison, were mainly relied on. The cultivations were 

 performed in closed tubes, half filled with the cultivating fluid. Every 

 precaution was taken both to prevent the entrance of other organisms 

 and to detect and eliminate from the series any cultivations which 

 proved to be contaminated. 



The cultivations were continued to the nineteenth generation, each 

 successive generation presenting identical morphological characters at 

 the various stages of its growth, and showing no diminution in the 

 capacity for growth, nor marked variation in the time and temperature 

 relations of its germination. From each successive cultivation fresh 

 cultivations were made, a microscopic examination was performed, some 

 capillary-tubes were filled with the cultivation and preserved for future 

 use, and, in most cases, a portion used for inoculation of a mouse. 



The first series of experimental inoculations were made, step by 

 step, as the cultivations proceeded, and when the results showed that 

 the Bacillus, though still actually growing, might be inoculated in 

 large quantities with impunity, a second series of inoculations was 

 made with the material which had been preserved in capillary tubes. 

 To this second series the objection might be made that the material 

 had deteriorated by keeping. The reply is to be found in the fact that 

 the earlier the cultivation the longer had it been kept, so that the 

 first cultivation might be two or three weeks older than the sixth, and 

 would have had more chance of deterioration, whereas it was found to 

 be equally virulent at the end of three months as when first used. 



In no case was I able to produce any symptoms or a fatal result by 

 inoculation with a later generation than the twelfth ; beyond that 

 stage a large quantity of actively germinating rods and spores pro- 

 ducing no result whatever. The diminution of virulence was very 

 marked, even at the eighth generation, both as regards the proportion 

 of animals affected and the rapidity of action with an equal dose. 



I do not desire at present to dwell upon any conclusions to be 

 drawn from these experiments. I would merely observe that, while 

 they suggest a means of protective inoculation with a modified virus, 

 the activity of which may be capable of exact determination, they 

 also point to a modification of the views which have been entertained 

 on the relations of the Bacillus anthracis to splenic fever. Whether 

 the facts are explicable on the hypothesis of alteration of the habitat 

 of the Bacillus, acclimatization, and incapacity for transplantation to a 

 different soil ; whether the same result would be attained by cultiva- 



