INFECTIOUS CATARRHAL FEVER OF HORSES. 
749 
■quently the history of an outbreak as to be almost the rule. It 
leads to this conclusion : That the iiiicro-org'aiiisin grains en¬ 
trance into the body by means of the inspired air, and entering 
by this system the most exposed tissues are the delicate and 
sensitive structures of the respiratory mncons membrane, pro¬ 
ducing a catarrhal inflammation, which by extension to contin¬ 
uous and contiguous organs causes the lesions most usually seen 
and which have been enumerated. If, perchance, these first- 
attacked organs should prove resistant, the infecting agent, cir¬ 
culating with the blood, fastens itself upon a susceptible organ 
in some other portion of the body. I have no intention of pre¬ 
cluding the possibility or denying the frequency of stasis in the 
various organs, especially the lungs, from extreme depression of 
the circulation due not only to the lassitude of the heart mus¬ 
cles but to the lack of resiliency of the arteries, from deficiency 
of sympathetic nerve supply, and death at the outset of the at¬ 
tack from asphyxia ; nor that the depression of the heart from 
the severity of the first onslaught may not be sufficient to pro¬ 
duce death by asthenia ; nor that the same phenomena mav not 
take place within the cranial cavity or the spinal marrow. 
But, where the initiatory effects are less pronounced, and the 
processes go on to localization of the disease in an organ, the 
attack then settles down to a self-limited disease whose severity 
is in consonance with the extent of the lesion and importance 
of the involved organ, which is usually in keeping with the 
clinical symptoms displayed by the patient. 
The observation by the various writers that those animals 
attacked at the beginning of the outbreak are most seriously 
affected, has been confirmed in my experience, and that very 
few of those who become victims as the outbreak is waning 
have such profound pyrexia or serious lesions is equally true. 
The tendency to gangrene is more pronounced in these in¬ 
flammations than in simple or sporadic inflammations, death 
from this termination being a frequent result in pneumonia. 
But often a very alarming symptom occurs during pneumonia 
in the expired air having a necrotic odor, extremely critical, 
