76 SCHULTZ AND JORDAN: STUDIES IN ANAPHYLAXIS 



we refer is, quantitatively at least, much more marked, and 

 apparently different from the fat phenomenon in cats. 



Large quantities of this material seemed distributed thruout 

 the body so that the voluntary muscles of the chest, the surface 

 of the right heart, the large veins up to the lungs, the diaphragm, 

 and especially the upper portion of the alimentary tract, appeared 

 whitish. The large blood vessels of the stomach and upper half 

 of the intestines stood out in striking contrast as a white net-work. 

 The large veins being at the same time greatly distended. 



After a lethal dose of horse serum the heart continues to beat 

 some time after cessation of respiratory movements, the ventricles 

 contract with rapidly diminishing force and frequency until finally 

 only occasional twitches are recorded, while the auricles beat 

 quite vigorously for some time later. The heart muscle, how- 

 ever, even after ceasing to beat rhythmically responds to mechan- 

 ical stimuli for some minutes thereafter. 



The respiratory muscles of the chest, the diaphragm, as well 

 as other voluntary muscles respond to mechanical stimuli after 

 stoppage of the heart. 



The appearance of the respiratory and circulatory phenomena 

 in the anaphylactic opossum, therefore, lies between those des- 

 cribed for the cat and those for the guinea-pig, and death prob- 

 ably ensues from asphyxia and low blood pressure. This low 

 blcod pressure being due to a weakening of the heart, increased 

 pulmonary resistance and a consequent engorgement of the right 

 heart and large veins, the primary cause of which is doubtless 

 to be found in the chemical and physical changes in the bleed 

 and tissue cells after a toxic dose of serum. 



