SPIROCHATA BALBIANII AND SPIROCHHTA ANODONTA. 49 
cheetes are Bacteria, which is quite possible, little progress is 
made in the idea of ‘‘ sexual polymorphism ” from that stand- 
point. : 
Conjugation.—Perrin mentions this as occurring very 
rarely. He says it ‘appears to take place when the crystal- 
line style melts in the gut of the oyster.” Little is known of 
conjugation in the Flagellata in general, and I have not seen 
it in these Spirochetes. 
Encystment.—lI am sorry that I have no evidence of this 
in any of my investigations, although the conditions pointed 
out by Perrin, such as starving the oysters or watching the 
forms at the periphery of the style, were carefully noted. 
I think that Mesnil in his review of this question of encyst- 
ment, as set forth by Perrin, was probably justified in regard- 
ing such forms—together with the formation of “male 
gametes ””—as representing really ‘involution forms,” result- 
ing from unusual or unfavourable environment. 
Further, Swellengrebel (10) accounts for the so-called 
encystment of 8. balbianii thus, in his own words: “ Quel- 
quefois il se forme des boules plasmatiques, de structure 
alvéolaire homologue a celles des Spirilles. Ce sont 14 vrais- 
emblablement les ‘ kystes’ de Perrin.” 
ENVIRONMENTAL Hrrgots. CuLrures. CHrmicaL REActIONs. 
Hffects of Temperature. 
At the temperature of the laboratory, 15° C. to 20° C., the 
Spirocheetes live in their natural medium from a few hours 
up.to 48 hours. At 30°C. the Spirochetes died in about half 
an hour or less. At low temperatures, as 5°C., the Spiro- 
cheetes lived four or five days. 
HKffects of iteration of Osmotic Pressure. 
In distilled water S. balbianii died very soon, though 
exceptions to this occurred. Even in the case of such excep- 
tions the membrane ultimately macerated and death resulted. 
VOL, 52, PART 1.—NEW SERIES. + 
