On Parasites. 



By A. T. Ozsard, M.R.C.S., England. 



jARASITES may be defined to be "living 

 organisms which derive their nourishment 

 wholly or in part from other living organisms." 

 Man by his complex organisation affords an easy prey 

 for every kind and variety of parasite : from the ex- 

 tremely minute organisms called Ba6teria which occur 

 normally in many parts of the body, up to the more 

 highly-developed, though certainly infinitely more repul- 

 sive-looking Tape-worm ! All the world over man is 

 infefled to a greater or less degree by parasites in some 

 form or another. In the Tropics, however, almost every 

 known (and probably many as yet unknown), variety of 

 parasite seems to congregate for the sole purpose 

 of adding to the many discomforts incidental to human 

 beings residing in such climes. 



But man may take comfort (?) in the fa6l that many 

 parasites are themselves infested with parasites ; in the 

 words of the poet :— 



" Big fleas have little fleas 

 On their legs to bite 'em ; 

 Little fleas have lesser fleas 

 And so ad infinitum." 



Parasites may be divided into the three following great 

 classes : — 



1. Parasites of the Animal Kingdom— (Zoo-parasites.) 



2. Parasites of the Vegetable Kingdom — (Phyto-parasites.) 



3. Parasites of extremely minute organic forms called generally— 

 Bacteria. 



