ENTOZOA IN RELATION TO PUBLIC HEALTH, ETC. 289 
malady, “or cestode tuberculosis , ” that, until lately, the only 
specimens of beef-measle ever seen, or at least recognised, in 
England, were those which were removed from cattle sub- 
jected to “ feeding experiments” by myself at the Royal 
Veterinary College. Neither Professors Simonds and Prit- 
chard, nor any other persons who assisted me in the investi- 
gations there conducted, had ever seen anything of the sort 
previously. The “ measles” were artificially reared in the 
animals by the introduction of the eggs of tapeworms, se- 
lected and obtained by myself and friends from the human 
body ; so that it may be said, without hesitation, that these 
experimental animals, instead of becoming diseased from 
parasitic germs by means of sewage-grown grass in an in- 
direct or roundabout manner, were infected by certain of the 
ordinary organic constituents of sewage, or faecal discharge, 
itself, in the most direct manner possible. Of course, in 
such cases we produce a more virulent form of the measle 
malady than can ever obtain under the ordinary circumstances 
by which the disorder is propagated, and, therefore, it is also 
desirable to remind Mr. Holland and those who support his 
notions that the presence of measles in cattle does not neces- 
sarily give rise to any conspicuous symptoms of suffering. 
It is true that the calf we experimented on nearly succumbed 
to the disorder, whilst the health of the older animals was 
only slightly affected ; but in these cases the numbers of 
six-hooked embryos actually traversing their bodies were 
collectively enormous — that is to say, many thousands. It 
needs but little reflection, therefore, to perceive that cattle 
fed upon sewage-grown fodder can never infest themselves to 
such an extent as to cause conspicuous suffering on their 
part. Yet at the same time it is perfectly clear that the 
likelihood of their becoming “ intermediary bearers” of the 
larvae of human tapeworms, is a thousand-fold increased by 
the fact of their being fed on grass reared under the condi- 
tions referred to. 
I may here remark, in regard to the invasion of parasites 
generally, that the question of suffering frequently, though 
not invariably, depends, firstly, upon the number introduced, 
secondly, upon the age of the “ bearer,” and thirdly, upon 
his sensitivity. Even in the case where a single entozoon 
takes up its residence in the brain or other important organ, 
the constitutional power of the host for resisting irritation 
may alone determine the degree of suffering or of fatality 
involved. My investigations with trichinae give similar results 
to those afforded by the measle experiments. It is astonish- 
ing what an amount of infection old animals will bear from 
