Louping III. G31 
speck, or a slight pimple — in others it is there, and full of blood 
which it has sucked up ; its body is blackish red and as large as a 
medium-sized pea. As far as I can see, all that this tick seems to 
be doing to its host is that it sucks its blood and produces locally 
no more (in fact less) injury than many other well-known animal 
parasites. When the tick settles on the skin of a human being, I 
am told that it sometimes produces a conspicuous local irritation 
with swelling ; the only instance in which I had the opportunity of 
seeing a child that had been bitten some hours previously by this 
tick, and from whose skin the mother had removed the tick, there 
was certainly nothing of any local irritation visible. But even 
assuming that the tick generally produces a local irritation and 
swelling, this would be no more than is the case with other skin 
parasites, particularly those that live on the blood of its host, for it 
is well known that such parasites secrete into the bite a substance 
which prevents the blood of the host, at the point of the bite, from 
coagulating, and thus keeps, as it were, the draught of the blood free 
by keeping the blood fluid. The undoubted fact, however, mentioned 
above and admitted on all sides, viz., that this same tick is found 
in the skin of animals that are, and remain, free of “ louping ill,” 
seems to me to finally dispose of the theory that the tick is the real 
or proximate cause of the disease “ louping ill.” This would still 
leave open the possibility of the tick being the carrier of infection, 
inasmuch as it might carry the virus from the soil to the body of 
the sheep, which by its bite it inoculates ; but this theory is, it must 
be confessed, somewhat remote. 
3. The disease is apparently communicated from one animal to 
another. It is well known that if a ewe contracts the disease, her 
lamb, with few exceptions, also becomes subject to the disease, but 
a lamb may have the disease without its mother becoming ill. The 
lamb always follows, and is always in close relationship to, the ewe. 
Amongst the first signs of illness is this, that the animal is dull and 
separates from the rest ; now, if the animal happens to be a ewe, it 
does not matter whether it separates from the rest of the flock or 
not, its lamb is sure to remain with it, and therefore, if the disease 
be of an infectious nature, we should naturally expect that sooner 
or later the lamb would take the disease from the mother. This is 
actually of common occurrence. But this would not be the case if 
the lamb takes the disease first, for then we should find two things 
happening ; first, that the lamb would not or could not follow its 
mother, consequently the ewe is not so much exposed to infection 
from its lamb ; and secondly, for this reason, that owing to the 
apparent neglect on the part of the ewe, and for other reasons (be 
it of charity, or of lucre, or both), the shepherd removes the lamb 
from the flock, taking it into a shed and nursing it, though, as a 
rule, this does not avail much. 
All these facts taken together would, then, strongly point to the 
disease being communicable from animal to animal. 
Another fact pointing in the same direction is this : that cattle 
also become affected with the disease, though they, as a rule, recover. 
T t 2 
