STAPHYLOLYSIN CONTENT OF SERUM 



93 



Thus 0.025 is the smallest dose which can completely hemolyze the given 

 quantity of red blood cells. 



The amount of antilysin is estimated by adding varying amounts of 

 serum to the constant minimal hemolytic dose of the staphylolysin and 

 determining what amounts of serum contain enough antilysin to prevent 

 hemolytic action of the staphylolysin. It is best to allow the staphylolysin 

 and serum to remain mixed for some time before adding the rabbit blood, 

 so as to give the antitoxin a chance to neutralize the toxin. 



As every normal serum contains a certain amount of antilysin, it is 

 necessary in order to obtain the pathological variations, to use a normal 

 serum as a control. Such a serum, o.i c.cm. of which just suffices to neu- 

 tralize twice the minimal hemolytic dose, was dried in vacuum and used by 

 Bruck, Michaelis and Schulze, as standard serum. 



Estimation of antilysin content of the standard serum: 



These mixtures were allowed to stand for one hour at 37 C. and then i 

 drop of rabbit's blood was added, allowed to remain for two hours at 37 C. 

 and twenty-four hours in the ice box. :' 



The standard serum was always freshly prepared in the form of a 10 

 per cent, solution in distilled water (o.i : i). 



In the above manner the antilysin content of the serum from patients 

 with distinct or suspicious staphylococcus infections was estimated. The 

 completely neutralizing dose of the standard serum (o.i above) was taken 

 as i and the neutralizing dose of the serum for examination compared 

 with this; if 0.05 c.cm. of a serum x neutralized the same amount of toxin 

 as o.i of standard serum, the antilysin value of the serum x was 2. 



From the comparative studies of Bruck, Michaelis and Schulze it was 

 concluded that most of the normal sera had values ranging from i down; 

 occasionally results as high as 5 were obtained. Out oj twenty -five cases of 

 staphylococcus infections nineteen gave values varying from 10 to 100. Fig- 

 ures as high as these can, according to these authorities, become of valuable 

 aid in diagnosis. 



Although these findings were corroborated by Arndt and others, the 

 method cannot as yet be classed among those of clinical diagnostic 

 importance. Similar study of other infections has not been undertaken. 



