LEUKINS AND LEUKOCYTIC EXTRACTS 363 



General Properties of Bacteriolysins. As with other cytolysins, 

 the bacteriolysins are thermostabile and resist heating to 60 C., being 

 gradually destroyed at temperatures ranging from 70 to 80 C. They 

 are likewise highly resistant to acids and alkalis, and when preserved in 

 a sterile condition with the addition of small quantities of a preservative 

 bacteriolytic serums for therapeutic and diagnostic purposes may re- 

 main active for long periods of time. Cholera immune serum as a diag- 

 nostic aid in making the agglutination and Pfeiffer bacteriolytic reac- 

 tions is best preserved in dry form, the serum retaining its activity under 

 these conditions for considerable periods of time. 



Normal Bacteriolysins. As a result of the contention of Metchnikoff 

 that bacteriolysins (fixateurs) are produced only upon the disintegration 

 of leukocytes, and that the plasma is accordingly free from these anti- 

 bodies, much experimental work has been done. The weight of evi- 

 dence is against this view, as both amboceptors and complements have 

 been demonstrated in plasma, although the quantity of bacterial ambo- 

 ceptors normally present in the body-fluids is quite small. It is quite 

 natural to expect that under normal conditions small amounts 

 will be present, as receptors are being constantly thrown off into the 

 blood, and leukocytes are, of course, being constantly formed and 

 destroyed. 



Specificity of Bacteriolysins. The bacteriolysins are highly specific 

 antibodies, and are useful in making the differentiation of bacterial 

 species. Group bacteriolytic reactions are less common as compared 

 to group agglutination, as was shown by Kolmer, Williams, and Raiziss 

 with the typhoid-colon group of bacilli. As a practical procedure, 

 however, the agglutination reaction is so easily secured as to be 

 the test of choice in making a differentiation between closely allied 

 organisms. As with the agglutinins, the influence of partial bac- 

 teriolysins may be removed by using highly immune serums in high 

 dilutions . 



Practical Applications. The bacteriolysins have considerable value 

 in the following procedures : 



1. In making a differentiation of bacteria, especially when the pres- 

 ence of cholera vibrios is suspected. 



2. In the diagnosis of certain infections, such as cholera and typhoid 

 fever. 



3. In the treatment of some infections with specific bacteriolytic 

 serums. 



