898 
OBSERVATIONS ON ENTOZOA. 
admirable arrangements displaying themselves in the ana¬ 
tomical construction of the vilest of parasites ; such as obtain, 
for example, in the body of the mange-louse. All I contend 
for is, that creative force, whether accepted as conclusive evi¬ 
dence of design or not, is responsible for all the facts notice¬ 
able, either in the one kind of animal or in the other. In 
short; let me sum up by remarking that orderly mystery, 
if not beauty, reigns everywhere. Be the practical teach¬ 
ings „ of parasitism what they may, there is no escape from 
the conclusion that parasites of all kinds, both internal and 
external, are natural developments accomplishing purposes 
of the most diverse kind. These creatures, I repeat, are not 
the resultants of diseased conditions. The Entozoa, as I 
have long taught, constitute a sort of specialised Fauna, occu • 
pying a peculiar territory. What our native country is to 
ourselves, the bodies of animals are to them. To attack, to 
invade, to infest, is their legitimate prerogative. The interior 
and exterior of “ hosts” form their proper temporary abodes; 
their entire structure and economy being expressly adapted 
to this end. 
You may be sure I have no desire to carry you into the 
mazes in which we should be involved by attempting a full 
consideration of this part of the subject; therefore I propose 
to leave vexed questions of this sort to philosophers like Mr. 
Herbert Spencer, of whose distinctive views in this relation 
you possibly may not have heard of, though they are point¬ 
edly alluded to in Professor Acland’s admirable c Harveian 
Oration for 1865* (p. 15). 
In this matter I have only one serious demand to make upon 
you. I pray you once for all to abandon the erroneous notion 
that internal parasites are of necessity generated as the result 
of certain diseased or morbid conditions of the tissues of the 
body of the host or bearer. Not alone amongst our country 
folk, but within the pale of the medical and veterinary pro¬ 
fessions, this foolish conception of cause and effect still holds 
its sway. Put it away from you. Abandon every precon¬ 
ceived opinion which like a thick veil operates to obscure your 
mental vision; and do not even listen to those who would un¬ 
wisely persuade you that worms, parasites, and Entozoa 
belong to the category of “ plagues” distributed as special 
punishments for human wrong-doing. 
Before I proceed in due course to pass in review the more 
important facts relating to the individual forms of Entozoa 
infesting our domesticated animals, it is necessary that I 
should yet further impress upon you the true character of 
Parasitism. Doubtless it is correct to acknowledge certain 
