170 METHOD OF COMPLEMENT FIXATION 



Serum Diag- ^ n c ^ ose association with the serum diagnosis of syphilis, com- 



nosis of Dis- plement fixation has been employed as a means for the diagno- 



eases Caused sis of conditions caused by the animal parasites and especially 



by Animal by the echinococcus. In the serum of patients suffering 



Parasites. f rom fa GSG infections, substances are found closely allied to 



the "lues reagine." They bind complement with an antigen consisting of 



an extract of the respective worms or hydatid fluid. 



Ghedini, Weinberg and Parvu and others have found that in most cases of echino- 

 coccus disease, the reaction is positive. If by operation the cyst is only incised, the re- 

 action becomes stronger or in few cases appears positive for the first time. After com- 

 plete excision of the cyst, the reaction disappears. According to Parvu and Laubry, a 

 positive test is found in the spinal fluid only when the echinococcus cysts have invaded 

 the brain. 



Ghedini described similar findings, caused by the ascaris, ankylostoma, 

 etc. 



