Report to the Water Research Committee. 



421 



five varieties, and found considerable differences as regards rapidity 

 of liquefaction, anaerobism, and other characters. The series includes 

 Eisenberg's B. liquefaciens, TJrankland's B. liquidus, and Zimmer- 

 mann's B. punctatus and B. devorans, and brings together a large 

 series of incompletely described forms with more or less probability. 

 The type is one of the commonest in the Thames, and a pronounced 

 putrefactive bacterium. 



Group XV includes three varieties not uncommon in the river in 

 the summer, and conforming to the type of B. subtilis in general 

 behaviour and in the characters of their highly resistant spores, the 

 germination of which was carefully traced. The total behaviour of 

 these varieties points to confusion between the hay bacillus (B. subtilis) 

 and the potato bacillus (B. mesentericus) , and I am driven to the con- 

 clusion that these two " species " are either identical or more similar 

 than is usually assumed. In any case both these forms are matched 

 by the varieties in this group, which my examination suggests are 

 varieties of one species. The wrinkled growth on potato cannot be 

 relied upon to separate them. 



Group XVI comprises a series of varieties of a yellow Sarcina of 

 the type S. lutea. I obtained five varieties, showing considerable 

 differences in liquefying power, and it was interesting to fird that 

 the Sarcina form—" packet form " — is not always maintained. 

 My cultures unite Frankland's S. liquefaciens, Lindner's S. flava, 

 and Schroeter's 8. lutea as mere varieties of one and the same 

 species. 



Group XVII was made for a rose-pmk or cerise-coloured micro- 

 coccus of the type of Zimmermann's M. carneus, not common, but 

 isolated several times in the winter of 1894 — 1895. The most 

 interesting point was the discovery that in early stages of division, 

 followed under high powers, it develops as a Sarcina, and several 

 facts point to the conclusion that the Sarcina form is a mere result 

 of slow development — e.g., in acid media — of Staphylococcus forms of 

 Micrococcus. My cultures unite M. carneus with Maschek's Coccus 

 ruber, Fliigge's Micrococcus cinnabareus, Zimmermann's M. cinna- 

 barinus, and certain forms often termed M. roseus, as well as Schroter's 

 Sarcina; rosea, as mere varieties of one form. 



Group XVIII is made for a curious form which serial cultures 

 under the high power shows to be no schizomycete at all. but a truly 

 branching micro-organism with acropetal growth and other charac- 

 ters which place it in the category of true fungi. Nevertheless it 

 breaks up into minute coccus-like oidial joints, so similar to a short 

 bacterium or oval coccus that it would inevitably be taken for such 

 if examined by ordinary methods only. I referred to it in 1895 as a 

 "false bacterium," and its history affords an excellent proof of the 

 necessity of microscopic cultures in these investigations. It presents 



VOL. lxi. 2 G 



