44 THE SNAKES OF SOUTH AFRICA. 
with the cold, but on the application of heat they soon regained 
all their vigour and vitality. 
The live snakes in the Port Elizabeth Museum cages are most 
active when the air is warm, and grow torpid in proportion to 
the lowering of the temperature of the air. When their cages 
are artificially heated they immediately revive. 
If a snake should find a cosy retreat, and provided there is 
sufficient sustenance in the neighbourhood, he will make that 
spot his headquarters, from which he will issue forth when hungry 
and scour the neighbourhood in search of food ; or else bask in 
the warm sunshine ready to beat a retreat on the least sign of 
danger. When the leaves begin to fall and the air grows chilly, 
a drowsy feeling begins to pervade his body which warns him it 
is time to seek out a cosy shelter for his long sleep. So he crawls 
into the innermost recesses of his lair, or seeks out a better one. 
Coiling himself up, he sinks into a condition of torpor. 
Most species of reptiles have the power of suspending anima- 
tion and lying in a death-like trance through the winter months, 
when the food on which they live is either very scarce or quite 
unobtainable. When animation is more or less suspended, an 
exceedingly small quantity of food-material is used up to keep 
the creature alive; whereas if it were active all the winter, it 
would require an abundant supply. This would mean that most 
species of reptiles would die of starvation. Those which had found 
enough food to tide them over till the summer season would not 
be in sufficient numbers to keep down the armies of living creatures 
which constitute the diet of reptiles. Thus would the balance of 
Nature be upset. 
PARASITES ON SNAKES. 
Snakes are frequently infested with parasites. Ticks often 
fasten themselves upon the skin between the scales. 
There once occurred an unusual mortality amongst the collection 
of live snakes in the Port Elizabeth Museum, which are kept in 
a long row of cages each four feet square and the same height, 
with plate-glass on the four sides. Noticing minute parasites 
upon one of the dead snakes, I made a microscopical examination 
of them, and found they were a species of lice somewhat smaller 
