BY R. GREIG SMITH. 623 



exciting cause of slimy rye-bread to Bac. vidgatus, after separat- 

 ing from the bread that organism and Bac. liodermos. Juckenack* 

 separated Bac. mesentericus in pure culture from a batch of ropy 

 rye-bread. Ecclesf found the slimj^ fermentation quite com- 

 monly in the bread of certain localities when it had been kept 

 warm for some time after baking. He traced the fermentation 

 to Bac. vulgatus and Bac. liode7"inos, the latter producing a greater 

 degree of sliminess than the former. We thus have cases of a 

 particular kind of fermentation — the alteration of the crumb of 

 bread into a gummy or ropy mass — induced by vnlgaius, mesen- 

 tericus and liodermos. This assumption of a common function 

 by these so-called species when considered with the fact that their 

 cultural characters are not very distinctive is enough to indicate 

 the probability of the species being really races of one bacillus. 



Ritsert's Bac. giunmosits and Happ's Bact. gummosutn do not 

 apparently differ greatly from Bac. vulgatus, and may well be 

 races. Lehmann and Neumann consider that they are allied to 

 that bacillus. 



With regard to the races which were separated in this research, 

 they appear to be allied not t© any particular member but to the 

 group as a whole. The race which was separated from cane juice 

 and which I have called the a type, appears, if the growth 

 on potato is an index, to be related to Bac. mesentericus ruber as 

 well as to Bac. vulgatus. The arborescent growth in gelatine 

 stab culture is peculiar to that race, and does not occur among 

 races which are identical in every other respect. The races of 

 the derived type are closely related to Bac. mesentericus so long- 

 as the cell protoplasm remains granular or spongy. Once the 

 protoplasm condenses, as it may do b}' repeated culti^ ation in 

 artificial media, the colour, the appearance aud the consistence of 

 the growth upon agar also change, and the race becomes related 

 to Bac. vulgatus, but still differs from it by reason of the spread- 

 ing, amceboid nature of the agar culture. The races when grown 



* Juckenack, ihid. 2te Abt., vii., 109, Ref. 

 t Eccles, Jour. App. Microscopy, iv. (3), 1222, Abs, 



