EDITORIAL OBSERVATIONS. 
55 
Dutch cattle into Cork by a certain consul for his own pri- 
vate use. As this event is said to have occurred less than 
thirty years ago, some one ought to remember the name of 
the consul, the number of the cows, and the fact of the 
disease first appearing among them, but none of these 
details have been satisfactorily made out. We have, how- 
ever, no objection to admit the truth of the speculation 
without this evidence, as the admission does not in the least 
affect the present investigation. 
The mode of propagation of the disease involves specula- 
tion number two , — Is it contagious ? Is the virus contained 
in the breath or the excretions ? Can the malady be artifi- 
cially induced ? All the evidence on these points is con- 
flicting. 
There is no doubt that the admission of a diseased animal 
into a cow-shed or field is followed in many instances 
by an extension of the malady to the sound animals ; but 
then it has to be remembered that pleuro-pneumonia often 
occurs where no fresh stock has been introduced for many 
months, and also that the disease often ceases with the first 
or second case, even though no means are taken to arrest its 
spread. Further, the direct transference by inoculation 
of the fluid from a diseased lung does not cause pleuro- 
pneumonia or any disease like it ; in fact beyond the pro- 
duction of local irritation it has no effect at all. 
Many stock owners deny the contagiousness of the 
disease altogether, while others who have observed its course 
in localities where the circumstances are favorable to its 
progress, are equally positive in the opposite opinion. The 
balance of evidence is decidedly in favour of the contagion 
theory, and we therefore accept that view of the nature of 
the malady as the correct one. 
Passing from the debatable points to facts which admit of 
only one interpretation, we have first to notice some of the 
peculiarities which are manifested during the progress of the 
disease. 
Every one knows what is the rule that obtains in refer- 
ence to contagious disease in general ; an outbreak occurs, 
two or three animals are attacked, and day by day fresh 
cases are added, until the majority succumb, perhaps none 
