Lamenesses of Sheep and Lambs. 
401 
of this disease, and its general prevalence amongst a stock, 
although an apparent argument in favour of contagion, depend, 
1 believe, merely upon the animals being equally exposed to the 
same morbific causes. These phenomena certainly indicate the 
operation of some common, and, it may be, wide-spread cause of 
disease, but cannot, without much corroborative evidence, be 
accepted as adequate proof of contagion. 
Again — the production of foot-rot by inoculation is recorded 
as an unanswerable argument in favour of its contagion. M. 
Gohier and others have applied the matter of foot-rot to 
" sound " (?) feet, and thereby succeeded in producing tlie dis- 
ease. But the most favourable experiments were by no means 
uniformly successful. Indeed, in M. Goliier's cases only two 
out of six took effect ; and in M. Favre's only twenty out of 
thirty-two.* Further, it is to be specially remarked, that the 
matter is quite innocuous when applied to the sound horn, and 
only acts when directly applied to the sensitive lamintT. Those 
who endeavour to prove the contagion of the disease by such 
facts must tlierefore admit that the matter of foot-rot is without 
effect when applied to the sound foot, and acts only when the 
quick has been laid bare. But this unavoidable admission is 
almost fatal to the argument ; for it shows that inoculation is 
only successful when practised in cases which must be certainly 
regarded as already in the incipient stage of the disease. In 
brief, the question stands thus : — A foot with a torn or abraded 
surface, for this is a sine qua non, comes in contact with the 
matter of foot-rot ; and then, say the contagionists, the disease is 
setup, foot- rot is established. But lesion of the horn, the first stage 
of the disease, has already occurred before the possible interven- 
tion of this contagion, and the subsequent stages will certainly 
follow provided the sensitive and irritable parts be exposed to 
cold, filth, or moisture. To these almost ubiquitous agencies 
we ascribe the onward progress of the case. It must, however, 
be admitted that the matter of foot-rot, when rubbed into the 
vascuhu- parts of the foot, is capable of acting in a similar man- 
ner. But the practical question arises: Is the matter of foot-rot 
the active cause which in ordinary cases produces the ulceration 
and suppuration of the later stages of the complaint? I think 
not, and for the following reasons : 1st. The quantity of matter 
even from a bad case of foot-rot is small, often not exceeding a 
drop or two in several hours ; and experiments show that even 
when recently collected and freely used it is not very active, 
and fails in many cases to produce any effect whatever. 2nd. 
Sheep with foot-rot are certainly little apt to move about, and 
* Youatt on Sheep, p. 530 and 533. 
