133 royal college oe veterinary surgeons. 
favour the outset of the disease, and increase its severity; but 
there is every reason to conclude that they are powerless to 
produce the poison where it w as not already in existence. 
These conditions constantly exist, but the disease only ap¬ 
pears at long intervals. 
Changes of the conditions of life, such as a transition 
from the open pasture to the close confined and impure 
stable, make the subjects more receptive of the poison than 
those already habituated to the confinement. So with re¬ 
gard to the spring and autumn changes of coat. There is 
an increased susceptibility at such times, and influenza will 
often prevail with unusual severity at such seasons. So it 
is also wfith cold, wet, intemperate seasons; these may confer 
a potential energy on the poison by laying the animal 
system more open to its attack, but they are powerless to 
produce it anew 7 . 
A favorite doctrine concerning the causation of influenza 
has been that it w as due to some modification of the atmo¬ 
sphere, or of the terrestrial magnetism. It has been sup¬ 
posed by some that it fell simultaneously on all parts of a 
continent or hemisphere, and by others, that its progress 
bore some relation to the motion of the earth ; one party 
supposing that its invariable course was from east to w r est, 
and another that it w 7 as from west to east. But hitherto 
there has been adduced no reliable evidence of the truth of 
any of these theories. It has been found to prevail under 
all extremes of heat and cold, moisture or dryness of the 
atmosphere, excess of ozone and its absence, high and low 
barometric pressure, and positive and negative condition of 
electricity. Moreover, all the extremes of these conditions 
are constantly alternating with each other wfithout producing 
any specific disease. They vary too greatly in different 
localities, wRile the disease goes on steadily advancing, and 
apparently unaffected by their vicissitudes. 
[To le continued .) 
ROYAL COLLEGE OF VETERINARY SURGEONS. 
QUARTERLY MEETING OE THE COUNCIL, HELD 
WEDNESDAY, JANUARY 8th, 1873. 
Members present. — The President and Professors 
Simonds, Brown, Pritchard, Williams ; Messrs. Balls, Broad 
Burrell, J. C. Broad, Cartwright, Cowie, Dray, Field* 
