526 Transactions of the Society. 



of human pathogenic bacteria were derived from this one parent 

 plant. It is to his preposterous claims for the organism that we 

 must attribute the neglect of later investigators to follow up his 

 observations. Leon Williams {15), one of his contemporaries, 

 dealt with a few points in Vicentini's work, and described a 

 method of staining the colonies with methyl- violet. W. D. Miller, 

 writing about the same time, would not allow the existence of 

 the organism at all as such, but divided it up into several kinds 

 of bacteria. His classification and nomenclature have been 

 partially adopted by later writers on the subject. We only pro- 

 pose here to refer to one of his kinds— namely, Bacillus maximus 

 huccalis— in the hope of clearing up some of the confusion which 

 has arisen over the use of the name. Miller applied the term 

 to the coarse iodine-reacting bundles of threads which we have 

 just described in the Leptothrix colonies. His description and 

 illustrations leave no doubt upon this point. He says it most 

 frequently occurs as parallel-running or crossing bundles of seg- 

 mented filaments which give the iodine reaction. Goadby (5), 

 while accepting Miller's classification of the so-called " ungrowable " 

 mouth bacteria, describes under B. maximus (in which he includes 

 B. maximus huccalis and Leptothrix huccalis maxima oi Miller) an 

 or<Tanism which he has grown on various media. His description, 

 however, in no wise tallies with Miller's. Goadby's organism is 

 motile and forms endogenous spores ; a few of its threads give the 

 granulose reaction on certain media ; he says nothing about its 

 running in parallel bundles. Bennett (^) describes B. maximus 

 huccalis ^s a large bacillus with segments 5-6 /a long (Miller 

 gave them as 2-10 /i) forming definite chains, which sporulate, but 

 only when grown outside the mouth ! He says it is non-motile, 

 and that he means the organism described by Miller as B. maximus 

 huccalis. He also says nothing about its iodine reaction nor about 

 its running in parallel bundles. We wish to suggest that the 

 B. maximus huccalis of Miller has not yet been grown artificially, 

 and that it cannot be so grown until the whole Leptothrix 

 colonies, of which it forms an integral part, have been cultivated 

 on artificial media. 



There seems to be no doubt that the fusiform bacillus has been 

 grown in pure culture, and also that it sometimes grows out into 

 threads. By supplying the cultures with various substances 



EXPLANATION OF PLATE XVII. 



Fig, 20. Part of a colony of Leptothrix, with " flowering head " branches. Drawn 



from a fresh preparation. The axis of this kind of branch consists of 

 a single swollen thread. Some branches are seen, in optical section. 



X 625. . . , .,, 



21. A "bottle-brush" branch. Drawn from a preparation stamed with 



Stephens' ink. x 600. 



