2 Veterinary Medicine. 



Finally venomous animals like bees, wasps, hornets, snakes, 

 etc., may be conveniently named with the rapacious. 



DIVISIONS OF PARASITES. 



Parasites are naturally divided into the vegetable and animal. 



Phytoparasites (phyton plant) or //a«^/ara5?;f« are exempli- 

 fied in the fungi of ringworm or thrush and the actinomyces of 

 lumpy jaw. 



Zooparasites (zoon animal) or animal parasites are represent- 

 ed by the worms, acari, etc. , etc. 



The Microbes, whether appertaining to the animal kingdom 

 {protozoa') or vegetable {bacteria'), will be considered along with 

 the infectious diseases to which they give rise. 



Parasites are further divided according as they live upon or 

 ■within the body of their host : — ectoparasites {ek out) and ento- 

 parasites {entos within). Each of these may be animal or vege- 

 table, thus we have : 



_ . r Ectophytes, Dermatophytes (derma skin) 



iictoparasites | Ectozoa, Epizoa (epi upon). 



Entoparasites {^;;;°P^f^^ (entos within) 



Again parasites are divided according as they are constantly and 

 compulsorily parasitic, or occasionally or accidentally parasitic ; as 

 they prey upon one species or genus of host or upon many ; or as 

 they prove parasitic only at one stage of their development. 

 Thus we find : 



Compulsory, Obligatory, Constant or Stationary Para- 

 sites which must live on the animal or vegetable host or perish. 

 They are unfitted to pass their existence elsewhere. Of these we 

 have examples in the psoric acari, lice, fleas, etc. , of the skin, and 

 many of the worms. 



Occasional, Accidental, Facultative or Temporary Para- 

 sites are such as can live on a given genus or species of host, but 

 which can also, if need be, fill out the round of their existence in- 

 dependently of such host. They have th^ faculty of living on this 

 host if opportunity serves, but this is not nece.ssary to their sur- 

 vival. Among these may be named leeches, trombidia, derma- 

 nys.sus, actinomyces, trichophyton, etc. 



Some temporary parasites pass only a certain stage of their 

 existence in or on the host, and yet this parasitism is essential to 



