NATURAL AND IMMUNE ANTIBODIES 147 



an extensive investigation of thei-molabilc baeteriolysins. They 

 concluded that the baeteriolysins are widely distributed in the 

 animal kingdom, are specific for the bacteria they act upon and 

 tliat they consist of thermostable antibody (amboceptor) and 

 thermolabile complement. In their opinion the antibodies, de- 

 veloped as a result of either vaccination or infection, have their 

 precursors specifically differentiated in the serum of normal 

 animals and that, in general, they are not substances formed de 

 novo. Coriell. Miller, and Sherwood (1940), working in this labora- 

 tory, confirmed many of the conclusions and extended the experi- 

 mental findings of Mackie and Finkelstein. They found the serum 

 of 20-hour-old kittens strongly bactericidal ; the serum of 3-day-old 

 rabbits moderately bactericidal ; and the serum of very young chicks 

 and chick embryos weakly bactericidal. Since these bactericidal 

 substances were inactivated at 56° C. and could be specifically ab- 

 sorbed they were apparently a lysins. 



/? Lysins, Leukins and Lysozyme. — These are bactericidal sub- 

 stances having many properties in common with each other but dis- 

 tinctly different from a lysins. While a lysins are quite active 

 against typhoid-colon, Salmonella and dysentery groups as well as 

 V. cholerae, B. pyocyancous, pneumococcus and streptococcus, the 

 /3 lysin and leukins are active against anthrax-subtilus and proteus 

 groups. Ledingham (1931) gives an excellent brief discussion of 

 these substances. It appears that their titer is not increased by vac- 

 cination and they are more thermostable than the a lysins. The 

 (3 lysins are found in normal sera, the leukins are present in 

 leucocytes, while lysozyme is present in various secretions and 

 tissues of the body. It is especially present in tears and cartilage. 

 Lysozyme is most active against a saprophytic micrococcus isolated 

 by Fleming. While 13 lysins are more thermostable than a lysins 

 they apparently are of complex nature. Pettersson (1928, 1929) 

 says that the portion analogous to amboceptor is denoted the 

 "activdble substance" and that corresponding to complement the 

 "activating substance," which is destroyed at temperatures be- 

 tween 63° and 70° C. Apparently the activable substance does not 

 combine with the bacteria unless the activating substance is 

 present. It is still unknown what role these substances play in the 

 body's defense. 



