SPIROCHAITA BALBIANII AND SPIROCHHTA ANODONTA. 51 
Perrin’s mixture of egg-albumen (one part) and sea-water 
(two parts) was found to be useful, even when no special 
care was. taken to concentrate the constituent sea-water to 
two thirds of its bulk, in order to make the mixture isotonic 
with ordinary sea-water. In this the Spirochetes remained 
alive for several days, though their movements gradually 
slackened. 
A weak extract of the liver of the oyster in sea-water— 
made by grinding together a little of the tissue of the 
organ and sea-water with carborundum powder and rapidly 
filtering, and to which excess of sea-water was added, the 
whole being made sterile as far as possible—was found to 
be effective, and the organism (S. balbianii) lived therein 
for at least twenty-four hours, sometimes even nearly forty- 
eight hours. It is difficult to maintain the sterility of the 
various artificial media tried, almost impossible in fact, for 
extraneous organisms are of necessity introduced with the gut 
contents of the Lamellibranch. 
A bolder experiment, namely, that of making a weak solu- 
tion of the crystalline style of Anodonta cygnea in sea- 
water and placing some living specimens of S. balbianii 
(from the oyster) therein, was tried. The Spirochetes lived 
for about an hour in the medium. 
S. anodontz lived for some days in an extract of the 
liver of the Anodon prepared in the water in which the 
Lamellibranchs lived. It also lived well in a preparation of 
the gut-contents of the host, up to the second day after the 
death of the host. 
It may be mentioned for the sake of completeness that 
some bacteriological media were tried. Among such media 
were broth, agar, blood-serum, and a mixture of ege- 
albumen and glycerine; but all were found to be useless in 
sustaining the life of the Spirochetes therein. 
Novy (18) mentions that he was unable to prepare a useful 
artificial medium for 8. obermeieri of relapsing fever. 
The inability to find suitable artificial media for keeping 
Spirochetes alive is an argument in favour of their Proto- 
