218 
Canker in Grass Snakes. 
stored with stagnant salivary secretions and as bacteria of 
many kinds always exist in the mouth due to the nature of a 
snake’s food, this is the region attacked. A slight sore — a 
bruise caused by striking at an annoying object, or a wound 
received during the swallowing of living prey- — is generally 
the start of the trouble. The sore becomes at once affected, 
and an intense irritation attended by a secretion of white 
cheesy flecks follows. 
Mr. J. Burtscher 1 records that the bacillus found in canker 
is about the size of that of typhoid fever and appears abund- 
antly as a diplobacillus, and both that and the single bacillus 
show capsule-formation. The bacillus is very mobile, and 
stained by the Van Ermengen method shows from five to 
twelve peripherally disposed flagella. The colonies are 
rounded with sharp edges, slightly raised, and show a faint 
irridescence seen against the light. It is highly pathogenic 
for cold-blooded animals and probably should be classed in 
the group to which Bacillus fluorescens liquefaciens Fliigge 
belongs. 
From my own observations I do not consider canker 
infectious. During the winter 1931-32 ten adult Grass 
Snakes ( Tropidonotus natrix) were hibernating coiled together 
among Sphagnum moss, and periodically I carefully raised 
the moss to see that the snakes were all right. In February 
I found one dead and a second dying, which I painlessly 
killed. I dissected both these snakes, which were in a similar 
condition. The stomachs contained a reasonable amount of 
food, bearing in mind their long fast, but the mouths were 
absolutely full of canker slime, and that of the dead snake 
gave off a disagreeable odour. These facts indicate that 
canker was the cause of death. The first snake must have 
been dead about three days, so that most probably it had 
had canker a few weeks before death, yet none of the others 
were even slightly affected, nor did any develop it subsequently 
although they all drank from and bathed in the same 
water. 
On 15th August, 1932, I caught a male Grass Snake 
{Tropidonotus natrix) which measured 3 feet 4 inches in length 
on the Findholme Estate, Doncaster. This snake was kept 
with others of the same species in a cage in a glass-house 
facing south, at my home in Fong Lane, Dalton, Huddersfield. 
On nth March, 1933, two weeks after waking from 
hibernation, a minute white fleck appeared on the right side 
of the roof of this snake’s (‘ Rasper’s ’) mouth. I removed 
the fleck immediately by gently bathing the mouth with 
l Burtscher, J . , ‘ Uber die Mundfaule der Schlangen ’ (Der 
Zoologische Garten (N.F.) Bd. 4, 1931), Leipzig. 
The Naturalist 
