510 
EVERGREENS AND FARM STOCK. 
investigations and experiments which have been carried out 
since that time have supported that view. 
It is not necessary to inform us that a cow introduced 
into a shed where pleuro-pneumonia has existed, showed 
symptoms of disease ten days afterwards , because we 
know that the same thing has happened when cows were 
put into sheds where no disease had previously existed, but 
we quite object to take such ordinary events as evidence of 
mediate contagion, or indeed as evidence of anything but 
the bare fact of the existence of the disease. 
We have no hypothesis to offer, but we rest on our oft- 
repeated proposition; take any number of absolutely healthy 
cattle, place them under circumstances which will render 
direct infection impossible, and then by any means produce 
the disease, and we abandon our position; until then we 
maintain it. The argument in favour of mediate contagion 
seems to be formulated thus : an outbreak occurs when no 
direct contact with diseased animals can be ascertained to 
have occurred, ergo, the transmission of the virus must have 
taken place in some mediate way; to this loose style of rea¬ 
soning we say prove the possibility of such a method of 
infection by experiment as may be done in all other contagious 
diseases. The attempt to furnish this kind of proof has been 
made repeatedly, and always with negative results. 
Extracts from British and Foreign Journals. 
EVERGREENS AND EARM STOCK. 
A good deal has been said on the poisonous nature of yew 
tree clippings, and every now and again we hear of cows or 
horses being poisoned by munching the branches that have 
been carelessly thrown in their way. The Journal of Forestry 
points out that the danger is not confined to the yew tree, but 
that many other evergreens possess the same deadly capability 
when in a half-withered state. Horses, and even pigs, have 
been destroyed by eating the clippings of laurel and box 
trees. Ivy prunings have proved as fatal to sheep, and it is 
