THE LTSINS. 133 



is able to effect a combination with the intermediary body, and a 

 zymotoxic group by means of which it destroys the corpuscle. Ehr- 

 lich has shown the close relationship between the complement among 

 the hemolytic factors and the bacterial toxins, inasmuch as he has 

 demonstrated the existence of complementoids which correspond to 

 the toxoids. As has already been stated, many of the complements 

 are deprived of their poisonous action by a heat of 56°. Ehrlich 

 has shown that this apparent destruction of the complement by heat 

 consists only in destroying the zymotoxic group. If an animal be 

 immunized with a hemolytic serum which has been rendered inactive 

 by heat, there is formed in this animal not only an anti-intermediary 

 body, but also an anti-complement. This procedure is analogous to 

 the production of antitoxin by treating an animal with a toxoid. 

 The anti-complement produced in this way is often quite as potent 

 as, sometimes more so than, that obtained by immunizing an animal 

 with an unheated or active hemolytic serum, just as a highly active 

 antitoxin may be obtained by treating an animal with a relatively 

 harmless toxoid. An anti-complement prevents the action of ite 

 specific complement by rendering it impossible for the latter to com- 

 bine with the intermediary body. It is possible that complements, 

 like intermediary bodies, may vary in the number of haptophorous 

 groups which they possess. If an intermediary body be possessed 

 of two complementophil groups, it may take up two mono-haptoph- 

 orous complements, or one di-haptophorous complement. 



Bordet ' combats Ehrlich's view that the union between the inter- 

 mediary body and the blood cell is a chemical one, and claims that it 

 is a phenomenon of surface absorption. The experiment upon which 

 this claim is based may be detailed as follows : If a guinea-pig be 

 treated with rabbit's blood, there is produced in the former animal a 

 hemolytic serum which will dissolve a given number of the blood 

 corpuscles of the rabbit. Having determined the amount of blood 

 which a given quantity of this serum wiU completely dissolve, pro- 

 vided that all the blood is added at one time to the serum, Bordet 

 added to the determined quantity of serum half this amount of rab- 

 bit's blood and then, after allowing it to stand for a while, added 

 the other half of the blood, when it was found that the serum dis- 

 solved only that portion of blood which was first added and had no 

 effect upon the second portion. He compares this to the following 

 simple experiment in surface absorption : If a small amount of methyl 

 violet be dissolved in a given volume of water, and a piece of filter 

 paper be immersed in this solution for a short time, the paper will 

 absorb all the coloring matter, leaving the water colorless. Now, if 

 the same amount of methyl violet be dissolved in the same amount 

 of water, and a piece of filter paper half the size of that used in the 

 first experiment be immersed in this solution, it also wiU absorb all 

 ' Anncdes de tlngHtiU Pasteur, 1900. 



