1893.] Psychology. 299 
As to quantity of food, in order to avoid all accidents which might 
result from indigestion, the Anaconda was given animals of moderate 
size; the largest it has swallowed is a kid of about 12 kilograms 
weight ; which represents one sixth the weight of the snake. Thereis 
no doubt, however, that in a wild state, a snake of its size could swal- 
low animals three or four times as large. ; 
M. Vaillant adds, in this connection, the following fact which shows 
the stretching capacity of certain snakes. In the menagerie of the 
museum, a viper from France, (Pelias berus) had to be put in the 
same cage with a horned viper, ( Cerastes.) As the individuals, 
although they belonged to different species, were about the same size, 
it was supposed that they would live peaceably together. It was a 
mistake. During the following night the Cerastes swallowed the Pelias 
berus, and in order to accommodate himself to his huge prey, his body 
was distended so that the scales which touch each other laterally, and 
even lap in its normal state were now so spread apart that between the 
longitudinal rows, a bare space equal in size to the scales was left. 
Digestion went on regularly, however, and the Cerastes did not appear 
to suffer. 
The author also remarked that snakes in general do not accept 
indifferently all sorts of food, but appear to exercise a choice. It is 
often difficult to induce a snake to take food for the first time, but 
once this is accomplished, it accepts more readily succeeding proffers. 
A Pelophilus madagascariensis has been known to refuse a variety of 
food for 22 months, when it atea starling, then a few other small birds 
and finally some rats, which are still fed to him without any difficulty, 
although previously they had been offered to him in vain. 
M. Vaillant also remarks that the residue of digestion are evacuated 
at a single time after each feeding, at the end of a certain number of 
days. However, it often happens that the fæces contain the residue of 
a former meal. (Revue Scientific, aont, 1892.) 
