NOTE ON A PINK-COLOURED SPIRILLIUM. 383 
lighter colour being due merely to the Spirilla not being 
abundant enough to cover altogether the fatty residues of 
the original feecal matter. 
As far as I know Spirillum has not been noticed hitherto 
to form coloured masses. Cohn, in his well-known paper, 
mentions only (spherical or elliptical) Micrococcus amongst 
the chromogenous Bacteria (Micrococcus prodigiosus and M. 
luteus forming pigment insoluble in water ; M. aurantiacus, 
M. chlorinus, M. cyaneus,and M. violaceus, forming pigment 
soluble in water). E. Ray Lankester describes (‘Quart. 
Journ. Mic. Science,’ vol. xiii, new ser., p. 409) a peach- 
coloured Bacterium (Bacterium rubescens), which forms pig- 
ment insoluble in water. Burdon Sanderson mentions (in 
Lectures on Specific Contagia, delivered at Owen’s College, 
Manchester ; see ‘ British Medical Journal,’ March, 1875) 
a blue Bacterium (insoluble). 
I have seen myself a purplish-blue Bacterium Termo 
(pigment insoluble in water) grow on flour-paste that had 
been given to me by Dr. Mackellar, of the Fever Hospital 
at Stockwell.! 
As has been mentioned above, the pigment is, in the 
present instance, contained in the Spirilla themselves, and 
is accordingly not soluble in water. Itis likewise insoluble in 
alcohol, but becomes, however, destroyed when left in it. It 
is insoluble in cold as well as in boiling chloroform ; the latter 
destroys the colour. Mr. F. J.M. Page, to whom I am indebted 
for the spectroscopic analysis, finds that it becomes more 
transparent when treated with adrop of weak caustic potash 
(40 per cent.), without, however, forming a clear solution ; 
and this solution, which is distinctly rose-coloured when 
examined with a small Browning’s spectroscope, shows an 
absorption-band close to the p line, and a suspicion of a 
second band in green, the red being at the same time 
shortened. 
The quantity at my disposal precluded a more detailed 
examination.” 
1 Virchow (‘Gesammelte Abhandlungen zur Wissenschaft]. Medizin,’ p. 
144) mentions several instances in which a rosy colour has been observed 
in putrid albuminates (casein) after the addition of mineral acids. Virchow 
himself noticed a rosy coloration of the rice-water stools in cholera after 
adding nitric acid. (The stools contained vibrio and ciliated monads). 
I need hardly say that all this is entirely different from the rosy colora- 
tion in our case. 
* With a view to obtain a greater quantity of Spiri//um rosaceum, | inocu- 
lated with it several cubic centim. of Cohn’s nourishing fluid for bacteria, 
having added to this fluid previously 1 per cent. of acetate of ammonia. 
The inoculated material was placed in the incubator and kept there at a 
VOL. XV.—NEW SER. cc 
