126 THE PRINCIPLES OF IMMUNOLOGY 



tivated ox serum for a time ordinarily sufficient for amboceptor ab- 

 sorption, washed free of serum and then treated with fresh horse 

 serum as a complement, no hemolysis occurs. Furthermore, under 

 these conditions no hemolytic immune body has been absorbed from 

 the ox serum. Hemolysis only occurs when fresh horse serum and 

 inactivated ox serum are added as a mixture. The interpretation is 

 that in this particular hemolytic system the amboceptor must be com- 

 bined with complement before the amboceptor combines with the cells, 

 or, in other words, that the complementophilic group of a free ambo- 

 ceptor has united with complement independently of the cyto- 

 philic group. 



Conglutinin. Bordet and Gay have studied the phenomenon de- 

 scribed in the preceding paragraph and have come to a different 

 conclusion as to interpretation because of their discovery of a 

 so-called " bovine colloid " in the ox serum. They attribute the 

 hemolysis in the Ehrlich-Sachs phenomenon almost entirely to the 

 amboceptor and complement of the horse serum. The complex 

 of guinea-pig cells and the two bodies in the horse serum serves 

 to attract the bovine colloid which augments the complementary action 

 of the horse serum so as to produce complete hemolysis and at the same 

 time produces marked agglutination of the cells. This colloid is 

 thermostable, is probably of protein nature, unites with a complex of 

 cells, amboceptor and complement, but does not act upon either normal 

 cells or cells saturated with amboceptor. Bordet and Streng in a later 

 study named the colloid " conglutinin." Streng found that the same 

 phenonemon could be demonstrated in regard to bacteriolysis and that 

 conglutinin is present in the sera of the ox, goat, sheep and certain 

 other herbivora but not in the sera of the cat, dog, guinea-pig, or bird. 

 Sachs and Bauer have not offered a better explanation of the phe- 

 nomenon unless the German theory of amboceptor is unqualifiedly 

 accepted. In our opinion both sides of this controversy deserve the 

 most careful consideration and much light may be thrown by further 

 study. The more modern views of immunological processes, influenced 

 as they are by the great advances in colloidal chemistry, tend toward 

 acceptance of the Bordet hypothesis of sensitization of antigen by the 

 thermostable constituent of cytolytic sera, at least until and unless 

 more conclusive contradictory evidence can be produced. 



Complement. Distribution. Complement is that thermolabile ele- 

 ment of normal blood which in the presence of amboceptor and antigen 

 completes the cytolytic reaction. As regards hemolysis, complement 

 in the presence of hemolytic amboceptor causes solution of the red 

 blood-corpuscles and thus renders the reaction visible. Complement 

 is found in the blood and in lesser amount in nearly all the other body 

 fluids except the aqueous humor of the eye. It is also found in inflam- 

 matory exudates and sometimes in transudates, but it is not present 

 in the urine, nasal secretion or the secretion of other glands except 

 that of the breast (milk). The amount in the blood is fairly constant 

 for any given individual, but during the first twenty-four hours after 



