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MANUAL OF BACTERIOLOGY. 



called. This zymotoxic group, however, is not an integral 

 part of the receptor, but is easily broken off from it, in the 

 manner described below. 



As is explained later, the power of the lysins becomes sus- 

 pended, but not lost, on being heated to 55° or 56° C. In this 

 condition they are said to be inactivated. They become active 

 again when certain fresh serum is added— not necessarily fresh 



Fig 52. — Receptor of the third order, and of some substance uniting with one 

 of them. — {Journal of the American Medical Association. 1905. P. 1369.) 

 c. Cell receptor of the third order — an amboceptor, e. One of the hapto- 

 phores of the amboceptor, with which some food substance or product of bac- 

 terial disintegration (/) may unite, g. The other haptophore of the ambo- 

 ceptor with which complement may unite, k. Complement, h. The hapto- 

 phore. z. The zymotoxic group of complements. 



lysin, but fresh normal serum. This will all be discussed 

 and explained later. For the present purpose it is sufficient 

 to bear in mind that lysin becomes inactivated and may be 

 reactivated. So the lysins act differently from agglutinins and 

 precipitins. They must have peculiar receptors which unite, 

 on the other hand, with the cells which they disintegrate and, 

 on the other, with a ferment-producing substance easily de- 

 stroyed by heat. These receptors must possess two haptophore 



