IDENTITY OF PLEURO-PN EUMONIA AND RUBEOLA. 645 
long-previous attack. In both the disease attacks the foetus 
in utero, and in both causes a tendency to abort. The ex¬ 
citement of an animal at the onset of pleuro-pneumonia, as 
shown by the proneness to rush, and other signs, is but a 
manifestation of delirium, such as always attends, more or 
less, the beginning of measles ; while the arched back, tender 
spine, and heaving flanks of the later periods would not be 
so observable in measles, owing to the 'different posture 
of the patient. Thus we find that in every essential parti¬ 
cular the signs are alike. To no other disease incident to 
man will this one correspond, while rubeola alone answers to 
the descriptions of pleuro-pneumonia among cattle. The 
two dovetail and fill a gap in the respective nosologies. There 
is another circumstance which seems something more than a 
coincidence, and contributes no small amount of corrobora¬ 
tive evidence. It is this. The last epidemic of rubeola 
which visited this colony came simultaneously with the 
epizootic pleuro-pneumonia. In 1859-60 this happened, and 
rubeola, scarlatina, and diphtheria raged concurrently with the 
rapid spread of the formerly unheard of disease among cattle. 
If those affections of the human family have subsided—died 
out, as it were—it is because there are no more materials, no 
more subjects, no more pure blood left liable to their infec¬ 
tion ; and so will they slumber, apparently extinguished, until 
a fresh generation grow up in pristine susceptibility. In the 
same way will it be with pleuro-pneumonia, unless, which is 
at least as yet unproven, inoculation prove a perfect prophy¬ 
lactic. In this also is there, by the way, another point of 
affinity, for inoculation was long ago proposed and practised 
as a preventive of rubeola. Succeed or not, there is, how¬ 
ever, no analogy between it and vaccination, for there are not, 
as in that case, two distinct species of animals to modify the 
virus, it being thus more like smallpox inoculation, known 
to be so hurtful. Possibly, if the latter virus were diluted, 
as the lymph is in the other process, it might be less virulent 
locally, yet equally efficacious. The pathological principle, 
although not precisely Jennerian, may nevertheless be fun¬ 
damentally the same, the virus repeating itself by catalysis; 
but upon such points much is as yet conjecture, as is the 
question of the suitability for human food of animals thus 
naturally or artificially infected. Those beasts w r ould at least 
be most agreeable to think of for this purpose which suffered 
neither; and the hope of helping to get them yet all into 
this normal condition has prompted this analogy, which, 
although it asserts no panacea, may, if confirmed, perhaps 
suggest what is far better—the means of absolute prevention, 
both of the typical disease and of its bovine analogue. 
