356 
ON PHTHISIS IN COWS. 
affection which deranges the habitual secretion of the milk is often 
followed by an affection of the chest, that has not the least 
relation to the former: and if it is also considered, that the greatest 
part of our cattle have, through a long succession of generations, 
being submitted to this regime, we shall not wonder that the 
organs of respiration in these animals should be exceedingly 
subject to disease. 
Experience has proved, that animals descended from parents in 
W'hom a certain system of organs has been enfeebled, are more 
than others disposed to an affection of those organs; and that 
this predisposition is greater in proportion to the number of 
generations through which it may be traced. 
The structure of the pulmonary organs is also, I believe, a 
general cause of these affections. In fact, if only the individuals, 
or the races submitted to the regime necessary for a constant 
secretion of milk were affected by maladies of the chest, we 
might believe that that regime was the only cause of the evil, and 
that they were only accidental local causes which developed 
these diseases in a greater or less number of other individuals : 
but this is not the case, and we see epizootic and enzootic ma¬ 
ladies of the chest develop themselves among the half-savage 
races of Russia, Poland, and Hungary, which yield milk only 
for the short space of time during which they nourish their 
young. Among these animals, always in the open air, there is 
some other cause for these complaints, and which I can find 
only in the peculiar structure of the lungs. 
Such are the two prevailing general causes which dispose the 
French cattle to diseases of the chest. 
It remains next to shew why the cattle in Paris are more 
exposed to these maladies than others. 
The bad system of management to which cattle are submitted 
in the country is well known. They pass suddenly from the 
warm, humid, and almost suffocating air of the cow-house to all 
the continual variations of the air without, sometimes hot and 
sometimes cold, now dry and presently moist, and by and by 
they return to the deleterious atmosphere of the stable. If these 
causes, well known determining causes, (to use a medical term) 
of pulmonary affections, had not influence on the losses which 
are experienced in Paris, I would not speak of them ; but as we 
shall presently find another reason for the frequency of these 
maladies among us, I am compelled to call your attention to 
them. 
In fact, if these causes of acute and violent inflammations of 
the chest always developed themselves, it would follow that the 
cows would either die, or would with much difficulty be saved ; 
