IDENTITY OF PLEURO-PNEUMONIA AND RUBEOLA. 641 
covery which perhaps most redounds to the credit of medicine 
as a science, or as the healing art, was in the linking together 
of separate orders of creation through the bond of disease. 
The same bovine herd which changes grass into flesh and 
milk for man's sustenance, also prepares an antidote to the 
direst ill that befalls his humanity. It will equally redound 
to its honour if our profession can find out a prophylactic, 
and pay back the boon, if not in kind, at least by intelligence, 
and rescue a race from a pest as dire to it as smallpox once 
was to us. Whether from motives of ideal gratitude to these 
bovine benefactors, or from veriest self-interest, an active 
spirit of inquiry is prompted which cannot let the secret 
which has so long baffled and eluded us lie much longer hid¬ 
den. The similarity or identity of the diseases of man and 
of animals is now so fully recognised that to trace a new 
affinity is nothing very wonderful. If, however, it be useful 
in removing a source of error in diagnosis or practice, it will 
be none the less important. To trace the identity of pleuro¬ 
pneumonia and rubeola may be nothing remarkable, but ex¬ 
ceedingly desirable to do in consequence of its probable 
practical utility. Both diseases are so prevalent, and so fully 
comprehended in many respects, that it may seem strange 
why the analogy should not have before been detected. Two 
circumstances seem to explain this oversight—1st. The 
obscurity of the first stage of pleuro-pneumonia as contrasted 
with the well marked conditions of the second stage. 2nd. 
The well-marked characters of the first stage of rubeola, and 
the comparative infrequency of the second stage. Remem¬ 
bering that it is by tracing the analogies of these stages re¬ 
spectively, and that the most prominent features are reversed 
in the two species of patients, it is easily understood how 
observation missed tracing the affinity. The symptoms of 
the first stage of rubeola in the human subject are familiar to 
all; but close watching is required to note the corresponding 
symptoms in the brute. The description given by systematic 
writers, and the observations which any one may make for 
himself, prove that these symptoms correspond in every par¬ 
ticular. There is a period of incubation of variable length; 
the onset in both is by the shiver characteristic of approach¬ 
ing febrile disorder, which soon follows. In both, the symp¬ 
toms are at first those common to other affections, and which 
at any other time than that of an epidemic or epizootic would 
hardly attract attention. In both it is, after some days of 
indefinite illness, that cough begins, as of a common cold; 
with coryza, puffy features, watering of the eyes, which are 
blood-shot; the mouth is clammy, and the secretions, as of 
