536 Professor David James Hamilton [March 8, 



WEEKLY EVENING MEETING, 



Friday, March 8, 1907. 



His Grace the Duke of Northumberland, K.G. P.O. D.C.L. 

 F.R.S., President, in the Chair. 



Professor David James Hamilton, M.B. LL.D. F.R.C.S.E. 

 F.R.S.E., Professor of Pathology, University of Aberdeen. 



Certain Seasonal Diseases of the Sheep, and the 

 Means of Preventing Them. 



Introductonj. — Perhaps a word of apology may be thonght neces- 

 sary by some members of my audience for the introduction of a 

 subject which, on the face of it, may seem to be suited for a medical 

 rather than for a general audience. While admitting that this might 

 be so were the subject treated from a purely technical point of view, yet, 

 in extenuation of my appearance here this evening, let me premise 

 what I have to say by reminding you that the diseases in question 

 are of great general scientific interest, and their study, owing to the 

 pecuniary loss sustained by the country from the mortality caused by 

 them, is one of the utmost economic utility. Further, the bearing 

 they have upon the pathology and prevention of many human diseases 

 is so intimate, that one cannot fail to see how the one may shed much 

 light upon the other and lead to the study of many diseases of man, 

 from a wide comparative, rather than from a narrow, exclusively 

 human, point of view. The study of the cause of disease is simply 

 one of the numerous sub-studies in the domain of biology, and one 

 of enormous importance, and the more widely the subject is 

 approached, the more likely will it be to lead to results of per- 

 manent value. Hence, from these various points of view, the theme 

 I have chosen for my lecture may perhaps be looked upon as worthy 

 of passing consideration by an audience so sympathetic with matters 

 scientific, in the broadest sense of the term, as that of the Royal 

 Institution always proves to be. 



The above diseases have claimed my attention for many years 

 past, first in a private capacity, thereafter under the auspices of the 

 Highland and Agricultural Society of Scotland, and, lastly, since the 

 year 1901, under the patronage of the Board of Agriculture and 

 Fisheries. In the year 1901, the Board of Agriculture appointed a 

 Departmental Committee to inquire into two of the diseases, namely, 

 those known as Braxy {Morbus subitarius ovis) and Louping-ill 

 {Chorea jjarahjtica ovis), and our Report on these was issued in June 



