BOOK II. 



PARASITES OF ANIMALS. 



IN dealing with this division of the subject it will be impos- 

 sible to give more than the faintest outline. Let it be borne 

 in mind that quite as much information might be offered by me 

 respecting the parasitism of each of the commoner domestic 

 animals as has been already advanced in regard to the helmin- 

 thism of man. That would by no means exhaust the subject. 

 Thus treated, a score of volumes, each equal in size to this, would 

 barely suffice to cover the whole ground of Parasitology ; and yet 

 there are not wanting intelligent persons who regard Helmin- 

 thology as unworthy of their attention. These persons form a 

 far too prevalent type of educated ignorance, and unfortunately, 

 it is just this class of people who enjoy the prerogative of edu- 

 cational responsibility. Even our metropolitan scientific insti- 

 tutions, expressly raised for the purpose of diffusing useful 

 knowledge, shrink from the revelations of parasitism. Domi- 

 nated by the miserable conception which judges that the 

 life-history of a worm cannot prove either interesting or 

 instructive to their audiences, they let slip the acquisition of 

 scientific data, a knowledge of which might enable them to 

 combat successfully some of the most terrible evils to which 

 human flesh, in common with that of animals, is heir. 



In the following few pages many new points of departure for 

 fresh scientific work will inevitably be suggested ; and if I only 

 succeed in conveying to the working student an adequate grasp 

 of the whole subject, especially in its bearings on the welfare 

 of the higher domesticated animals and man, I shall have 

 accomplished all that I can reasonably hope to do within the 

 restricted limits of space at my command. 



