556 
Louping-ill in Sheep. 
of whether a previous convulsion or tetanic stage has been observed 
or not. The result, as might have been expected, is that when a 
series of cases of so-called louping-ill are submitted to the test of 
post-mortem examination, they have to be sorted out under several 
different headings, and the confusion in the matter is so great that 
one has difficulty in determining which of the morbid conditions 
should have the term louping-ill reserved for it. 
Without attempting to decide which of them has the best claim 
to the name, I feel warranted in saying that the following are the 
principal morbid conditions at the present time grouped under the 
head of louping-ill : — 
1. Pyiemic spinal meningitis, caused by pyogenic bacteria. 
2. Gastritis and enteritis from indigestible substances (wool, 
sand, dried grass) in the stomach or intestines. 
3. Disorders of brain functions, paralysis, and general weakness, 
with, in some cases, excess of cerebro-spinal fluid in the cranial 
cavity, but without gross lesions in any of the organs of the body. 
The first two of these conditions cover most of the cases of 
louping-ill in lambs, and the third includes the bulk of the cases in 
adult sheep. The cause or causes of the last of these groups of cases 
have not yet been satisfactorily determined, but all the experiments 
hitherto made indicate that these cases are not bacterial or trans- 
missible by inoculation. 
Prevention. 
1. Pijcemic spinal meningitis . — This includes those cases of 
louping-ill in which the essential lesion is an abscess involving the 
spinal cord or its coverings. 
Before discussing the possibility of preventing cases of this kind, 
it will be necessary to make further reference to the cause of the 
disease. The abscesses owe their origin to the presence of germs, 
and before anyone can confidently say whether it would be possible 
to devise and carry out measures that would prevent the entrance 
of these germs into the system of the sheep, he must be able to 
figure to himself the natural mode of infection, and the habit of the 
parasite. 
The common methods by which disease-producing germs obtain 
access to the animal body are : — 
1. The alimentary canal, with the food or water. 
2. The air passages, with the inspired air. 
3. Wounds or abrasions of the skin. 
4. The umbilicus or navel (during the first few days of life only). 
In infection by inhalation, especially in diseases characterised 
by pronounced lesions (such as abscesses), the lungs or their 
lymphatic glands are almost always the seat of disease, and, in like 
manner, structural alterations of some part of the alimentary tube 
or its associated glands are generally present when the disease germs 
have been taken in with the food or water. In the cases of pyamiic 
meningitis in lambs that have come under my notice no abscesses 
