STREPTOCOCCUS PYOGENES. 497 



by means of a hypodermatic needle, and each c.c. added 

 to a tube of broth, in order to produce an adequate 

 development of the cocci, which are found in small 

 numbers in the bloodvessels. Petruschky is of the 

 opinion that the cocci can best be shown in blood by 

 animal inoculation. Having withdrawn from the 

 patient 10 c.c. of blood by means of a hypodermatic 

 syringe, under aseptic precautions, he injects a portion 

 of this into the abdominal cavity of a mouse, while the 

 other portion is planted in bouillon. Mice thus inocu- 

 lated die from septicaemia when virulent streptococci 

 are present only in very small numbers in the blood. 

 If a successful inoculation takes place we can, through 

 the absence or presence of the development of capsules, 

 often differentiate between the pneumococcus and the 

 streptococcus, which cultures may fail to do. The 

 morphological and cultural characteristics of the strep- 

 tococcus give us, unfortunately, no absolute knowledge 

 as to the influence which the protecting serum will 

 have. The actual test is here our only method. The 

 detection of the streptococcus in the blood is in itself 

 an unfavorable prognostic sign. 



The blood cultures in perhaps the majority of cases 

 of septicaemia give no positive results, for many of 

 these cases develop their symptoms and even die from 

 the absorption of toxins from the local infection, such 

 as an amputation wound or an infected uterus or peri- 

 toneum, and the bacteria never invade the blood. When 

 we get negative results we are, as a rule, utterly unable 

 to test the case with curative serums with any accuracy, 

 for the sepsis may be due to either the streptococcus, 

 colon bacillus, staphylococcus, or a number of other 

 pathogenic varieties of bacteria. 



32 



