PARASITES OF MAN AND DOMESTICATED 

 ANIMALS. 



INTRODUCTION. 



The edifice of the world is only sustained by the impulse of hunger 

 and love. — Schiller. 



The ntimerous letters received during the last fe-w years 

 from farmers, stock-raisers, dairymen, poultry-raisers and 

 others, show that many of our domesticated animals suffer 

 more or less from parasites, and as these special branches of 

 farming receive now more and more attention, a short treatise 

 on parasites will be of some use. 



The term parasitism is used in this treatise in its widest 

 sense, and the parasites mentioned in it may be living upon 

 the hosts infested, permanently or only for a short time. 



In the struggle for existence animals and plants have 

 been forced to adopt all sorts of peculiar methods to live ; 

 most of such methods are above-board, but others are at 

 least dishonest or even worse. The majority of such beings 

 are like honest farmers and mechanics ; they till the soil or 

 otherwise work for a living. Many, however, are not so 

 honest, they rob the substance of others and thrive upon 

 material not produced by them or belonging to them. These, 

 at first perhaps by force of circumstances, became in the be- 

 ginning simply occasional beggers or robbers, but as they en- 

 joyed such an easy life, in course of time their off-spring be- 

 came so modified in form and structure that they could no 

 longer take care of themselves but had to lead the dependent 

 mode of life first adopted by their parents. Most of the so- 

 called parasites belong to this group of organisms, be they 

 animals or plants. They lead all sorts of peculiar and dark 

 existences; some simply utilize the host, or the organism up- 

 on which or in which they are found, as a means to reach 

 the source of needed supplies, and in this case the hosts are 



