VETERINARY PARASITOLOGY 
INTRODUCTION 
A PARASITE may be defined as a living organism which, 
for the purpose of obtaining nourishment, passes the 
whole or a portion of its existence upon or within another 
living organism. Parasites may be divided into two 
main classes : 
1. Animal parasites, or zoo-parasites. 
2. Vegetable parasites, or phyto-parasites. 
Of these, the latter are by far the smaller group, and 
all those which affect the domesticated animals belong 
to the fungi. They are a series of very low forms of 
plant-life, and their common mode of reproduction is 
asexual, by means of spores. The Dermatomycoses, 
which embrace the three chief species of ringworm, as 
found in the domesticated animals, may be taken as 
the type. 
Animal parasites are all obligatory at some period of 
their existence, but in many the host is only required 
during a portion of the life of the parasite, and so one 
speaks of “ fixed parasites ’’ and “‘ transitory parasites.” 
The Tzniz serve as an example of the former, as they 
are unable to maintain their existence apart from their 
host, while of the latter the Gstride, the bot-flies, are 
typical. 
Transitory parasites are chiefly confined to those 
parasites whose habitat is on the surface of the skin, 
or within or near the natural openings, such as the 
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