PART 0.— MECHANISM. 
LESIONS. 
Gar and Southard,® 1907, found in guinea pigs dying from a second 
injection of serum, and in those which had severe symptoms and were 
later chloroformed, lesions which are interpreted as explaining the 
mechanism of anaphylaxis. They state that ^The study of the histo- 
pathology of this serum disease shows us that we have to deal with an 
intricate cell reaction demonstrable by definite cell lesions.’^ Con- 
siderable hemorrhages, rather definitely localized, are the character- 
istic gross lesions. The hemorrhages may be in one or several organs, 
gastric hemorrhages being especially frequent. Alicroscopically there 
are, in addition to the naked-eye hemorrhages, minute interstitial 
and oozing hemorrhages. Thev also found fttav changes in volun- 
tary muscle fiber, heart muscle fiber, and in nerve fiber. 
That the conjestion and dilatation of the blood vessels found in 
the abdominal cavity and the hemorrhages upon the mucosa of the 
stomach are not characteristic of death due to anaphylaxis is evident 
from the fact that we have found that in molent death produced by 
large subcutaneous injections of chloral cyanhydrin or hydrocyanic 
acid there are somewhat similar congestions and hemorrhages.^ Fur- 
ther, we have lately had the opportunity to examine a guinea pig 
whose death was caused by suffocation in an atmosphere of carbon 
dioxid. In the stomach and lungs of this guinea pig lesions were 
found that, so far as the congestion and hemorrhages are concerned, 
were somewhat similar to those described in guinea pigs dying from a 
second injection of horse serum. 
We were especially struck by the fact that the macroscopic con- 
gestions and hemorrhages may be absent in guinea pigs poisoned by 
intracerebral injections. 
Further, this congestion and dilatation of the vessels of the abdomi- 
nal cavity is well known to occur in shock and other states. 
We were also unable to confirm Gay and Southard’s findings in 
regard to the fatty changes. 
« Journ. Med. Research, May, 1907, p. 143. 
^ Rosenau, M. J., and Anderson, John F.; A stomach lesion in guinea pigs caused 
by diphtheria toxi n e and its bearing on experimental gastric ulcer. Journ. Infec. 
Dis., vol. 4, No. 1, Jan., 1907, p. 1-7. 
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