86 REVIEW. 



often found in diseased tissues, belongs to the genus Bacillus, 

 "although their genetic connection is still unknown (dunkel)/' 

 Our author has himself ])ointed out the great probability of tlie 

 normal existence of Bacillus-fibres in the stomach of cattle. 



(6) Lamenting the slight knowledge which we have of the 

 physiology of Bacillus, especially from the chemical point of 

 view, Cohn comes to the conclusion that for their perfect develop- 

 ment free exposure to the air is necessary, while their ferment 

 activity goes on with great intensity in vacuo. But putrefaction 

 proper is not produced by Bacillus ; to effect it " the ferment of 

 putrefaction," that is Bacteriuvi icrmo, must be present, hence 

 the generic difference of these forms is again indicated.^ 



(7) With the facts in his mind, of which an account has just 

 been given, the delight of Cohn may be conceived, when he heard 

 from I)r. Koch of his investigations into the setiology of splenic 

 fever, and on his seeing his experiments and his specimens ; these 

 were examples of the species called Bacillus anikracis, but the 

 difference between them and the Bacillus of hay infusions — 

 B. suhtilis — are so slight that the same figures are used in ex- 

 planation of both papers. 



Cohn's last words are full of hojie ; although we know not yet 

 if the Spirochete of marshy water and of recurrent fever, the 

 Micrococci of foul springs or of decayed food, and of typhus or 

 diphtheria, have severally any genetic connection ; yet the great 

 light that has of late, that is, since these subjects have been 

 studied with any energy, been thrown on them, in so short time, 

 bids us hope for more to come. 



Tlie title of Dr. Koch's paper is ' The ^Etiology of Splenic 

 Pever (Milzbrand-Krankheit), based on the History of Develop- 

 ment of Bacillus Anthracis.'' 



1. The introduction relates how the writer was brought to the 



^ As in Colin's last paper there is a great deal of species-making:, with 

 •which compare Prof. Laiikester's remarks on the subject (' Quart. Journ. 

 Micr. Sci.,' July, J 876), it is right to note that he here says that he con- 

 siders his genera Micrococcus Bacterium, Bacillus, Vibrio, Spirillum, and 

 Spirocho'fe as natural, but his species as purely provisional ; 1 fully expect 

 that continuous observations would show that genetic relationships exist 

 between some of these ; and I would draw attention to the fact that in his 

 last classification Leptothrix'x?, a term oi generic value. Prof. Lankester has 

 called my attention to a paper by Dr. Warming, of Copeniiagen, to whom 

 Cohn was indebted for many of his new specimens, described in the pre- 

 vious essay; the Danish naturalist has been good enough to give at the 

 conclusion of his paper a resume in French ; from it 1 will simply quote 

 "Les bacteries sont donees en realite d'une plasticite illimilee, et je crois 

 qu'il faudra renoncerau sysleme de M. Colin et de quclques autres savants, 

 qui caracterisent les genres et les especes d'apres leur forme." The extent 

 of Dr. Warming's investigations entitles any opinion he may put forward to 

 a most respectful hearing. — F. J. B.] 



