70 Ward . — A Violet Bacillus from the Thames. 
unable to determine the causes here at work, but neither 
temperature nor impurity of culture were among them. 
It is evident that this is a well-marked Pigment-Bacterium, 
and at first sight one might suppose it not difficult to identify. 
On looking further into the matter, however, it turns out that 
several violet or deep blue Pigment-Bacteria are described, 
some of them very vaguely. So far as I have been able to 
discover, the following are the forms hitherto introduced into 
the literature. Passing over Schroter’s Micrococcus violaceus 1 , 
a form described as not liquefying the gelatine, and non-motile 
— though in other respects it would seem to be very similar 
to the elliptical cocci got in old gelatine-cultures of the 
Thames species, and in any case it must be regarded as 
imperfectly described — there are at least nine or ten alleged 
specific forms in the handbooks, viz. B. violaceus of Plagge and 
Proskauer, usually regarded as identical with their B. lividus 2 ; 
B. janthinum of Zopf 3 ; B. membrauaceus amethystinus of 
Eisenberg 4 ; B. violaceus Laurentius of Jordan 5 ; B. violaceus 
of Frankland 6 ; B. coeruleus , Smith 7 ; B. coeruleus of Voges 8 ; 
B. violaceus of Mace 9 ; B. berolinsis indicus of Claessen 10 ; and 
B. indigoferus of Voges n . 
Assuming these to be all autonomous forms — which, how- 
ever, is extremely doubtful — I now proceed to examine their 
principal characters with reference to the Thames form. Frank- 
land’s species — B. violaceus — naturally suggests itself, seeing 
that it was also reported from the Fondon as well as the 
Berlin waters ; but it is noticeable that it was first observed 
in the Spree. 
Apart from small differences as regards size and manner 
1 Schroter in Cohn’s Beitrage, Bd. i, p. 109 ; and Adametz, Die Bakterien der 
Nutz- und Trinkwasser, Wien, 1888. 
2 Zeitschr. f. Hygiene, Bd. ii, p. 463. 3 Die Spaltpilze, 1885, p. 68. 
4 Bakteriol. Diagnostik, 1891, p. 421. 
5 Report of State Board of Health, Massachusetts, 1890, p. 838. 
6 Zeitschr. f. Hygiene, Bd. vi, p. 394. 
7 Medical News, 1887, p. 758. 
8 Centralbl. f. Bakt., Bd. xiv, 1893, p. 303. 
9 Annales d’hygiene publ. &c., t. xvii, 1887. 
10 Centralbl. f. Bakt., Bd. vii, p. 13. 
11 Ibid., Bd. xiv, 1893, p. 307. 
