INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 1019 



who has found that, when the Bacillus anthracis is cultivated in 

 aqueous humour, after about six generations it loses its infective 

 property. Then as Buchner's experiments proceeded, the appearance 

 of the growing organism was found to undergo gradual modification. 

 Instead of the cloud at the bottom of the vessel, a scum began to make 

 its appearance — at first greasy-looking and easily broken up — consti- 

 tuting, so far as appearances went, an intermediate form between the 

 two organisms ; and in course of time the scum became drier and 

 firmer, and at length the modified Bacillus anthracis was found to be 

 capable of growing in an acid hay-infusion, and to present in every 

 respect the characters of the hay-bacillus. 



The converse feat of changing the hay-bacillus into the Bacillus 

 anthracis proved very much more difiicult. A great number of ingeni- 

 ous devices were adopted by Buchncr, who was, nevertheless, con- 

 tinually baflled, till at last he attained success in the following 

 manner. Having obtained the blood of a healthy animal under anti- 

 septic precautions, and dcfibrinated it also antiseptically, and having 

 arranged his apparatus so that the pure dcfibrinated blood, which was 

 to be the cultivating medium, should be kept in constant movement, 

 so as to continually break up the scum, and also keep the red cor- 

 puscles in perpetual motion so as to convoy oxygen to all parts of the 

 liquid — in this way imitating, to a certain extent, the conditions of 

 growth of the Bacillus anthracis outside the animal body, within which 

 the hay-bacillus could not be got by any means to develop — he pro- 

 ceeded to cultivate through numerous successive generations. A 

 transitional form soon made its apjiearance ; but the change advanced 

 only to a limited degree, so that further progress by this method 

 became hopeless. The modified form hitherto obtained failed entirely 

 to grow when injected into the blood of an animal. On the contrary, 

 it was in a short time completely eliminated from the system, just like 

 the ordinary hay-bacillus. It had, however, been observed by Buchner 

 that spores had never been formed by the bacillus growing in the 

 dcfibrinated blood ; and it occurred to him that, perhaps, if it were 

 transferred to extract of meat, and induced to form s])ores there, the 

 modified organism might yet grow in the blood of a living animal. 

 The carrying out of this idea was crowned with success ; and, both in 

 the mouse and in the rabbit, Buclmcr succeeded by injecting various 

 difl:erent quantities containing the ox-ganism iu difierent animals. 

 When large (quantities wore introduced, the animals died ra})idly li-om 

 the merely chemical toxic effects of the injected liquid ; but in some 

 instances, after the period for tliese primary efiects had passed, a fatal 

 disease supervened — attended, as in autlirax, with great swelling of 

 the spleen, tlie blood of which was found i)eopled as in that affection 

 with newly fcjrmed bacilli ; and the s])leens affected iu this way were 

 found to communicate anthrax to healtliy animals, just like those of 

 animals which had died of ordinary splenic fever. 



Supposing these results to bo trustworthy — and the record of them 

 bears all the stamp of autlionticity — I need scarcely point out their 

 transcendent importance as bearing upon the origin of infective 

 diseases, and their modifications as exhibited in ej)itloniic8." 



