70.2 OBSERVATIONS ON THE LUNG PLAGUE OF CATTLE. 
ground that the sale of the timber which is used for fitting 
up the ships in which cattle are brought from the United 
States is to be looked upon as a cause of disease. 
If we can succeed in guarding against the ordinary source 
of infection—the living diseased animal —we shall not have 
much trouble in dealing with outbreaks which arise from 
mediate contagion, especially of such a remote order as those 
to which we have referred. 
Extracts from British and Foreign Journals. 
OBSERVATIONS ON THE LUNG PLAGUE OE CATTLE 
(PLEURO-PNEUMONIA CONTAGIOSA BOVINA).* 
By Professor James Law. 
Continuedfrom p. 622. 
Causes Influencing the Spread of the lung Plague Southward. 
-—A glance at the connections of New York southward will 
show why the plague should have extended in this direction 
rather than west or north. In the first place the cities of Newark, 
Elizabeth, New Brunswick, Trenton, Easton, Reading, Bur¬ 
lington, Germantown, Camden, Philadelphia, Wilmington, Balti¬ 
more,Washington, Alexandria, &c., drew their supplies of fresh 
dairy cows from the great marts to which western cattle were 
sent. From the comparatively close proximity of these cities 
they respectively drew their supplies from New York, Phila¬ 
delphia, or Baltimore, according to which market was at any 
moment overstocked, so as to depreciate the value of the stock. 
Thus Philadelphia and Baltimore were early infected from New 
York and Jersey City, and once infected they reciprocated freely 
by furnishing contaminated cattle to the market of New York, 
whenever that market was poorly supplied, or they themselves 
glutted. Thus, too, it soon came about that all the lesser cities 
drew constant supplies of infection from these three great 
plague-stricken centres. All of the cities named were growing 
places with much unfenced land laid out for building, or held by 
soeculators in waiting for purchasers, and upon these the herds 
of different owners pastured in common, and infected each other, 
* Extracted from the ‘ Eirst Annual Report of the Cornell University 
Experiment Station, 1879—SO. 5 
