Mic&ocuccirs AUREUS. 275 



If one inject into the circulation of the rabbit through 

 a vein of the ear, or in any other way, from 0.1 to 

 0.3 c.c. of a bouillon culture or watery suspension of 

 a virulent variety of this organism, a fatal pyaemia 

 always follows in from two and one-half to three days. 

 A few hours before death the animal suffers frequently 

 from severe convulsions. Now and then excessive 

 secretion of urine is noticed. The animal may appear 

 in moderately good condition until from eight to ten 

 hours before death. At the autopsy a typical picture 

 presents : the voluntary muscles are seen to be marked 

 here and there by yellow spots, which average the size 

 of a flaxseed, and are of about the same shape. They 

 lie usually with their long axis running longitudinally 

 between the muscle-fibres. As the abdominal and tho- 

 racic cavities are opened the diaphragm is often seen to 

 be studded with them. Frequently the pericardial sac 

 is distended with a clear gelatinous fluid, and almost 

 constantly the yellow points are seen in the myocar- 

 dium. The kidneys are rarely without them ; here 

 they appear on the surface as isolated yellow points, 

 or, again, are seen as conglomerate masses of small 

 yellow points which occupy, as a rule, the area fed 

 by a single vessel. If one make a section into one 

 of these yellow points, it will be seen to extend deep 

 down through the substance of the kidney as a yellow, 

 wedge-shaped mass, the base of the wedge being at the 

 surface of the organ. 



It is very rare that these abscesses for abscesses the 

 yellow points are, as we shall see when we come to study 

 them more closely are found either in the liver, spleen, 

 or brain ; their usual location being, as said, in the kid- 

 ney, myocardium, and voluntary muscles. 



