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Scientific Proceedings (130) 



and Levin 7 ). Since the publication of the preliminary studies, 

 however, several observations have been made which led to some 

 changes in the original procedure; also, a modified technic has 

 been evolved which is employed as a check on the original one. 

 The improved method discussed in the following resume embraces 

 both the original and modified procedures. 



The Antigen 



Preparation of Alcoholic Extract : Beef heart is freed from fat 

 and fiber in the usual manner and passed several times through a 

 meat grinder. It is then spread on a platter and dried by means 

 of a revolving fan. The dried plates are broken up into small 

 particles and ground in a mortar or coffee grinder. The ground 

 muscle is then extracted with ether at ice-box temperature until 

 supernatant ether is free from coloring matter. Between three 

 and four ether extractions will bring this about. At the end of 

 the final extraction, the ether is filtered off and the ground muscle 

 dried for some hours at room temperature until free from ether 

 odor. 



Given quantities of dried material are placed in Erlenmeyer 

 flasks. A quantity of 95 per cent, alcohol equivalent to five times 

 the amount of dried material is added to each flask. The extrac- 

 tion is carried out in the ice-box from nine to ten days. After 

 that period, 10 c.c. of supernatant extract is pipetted into a large 

 test tube and the color compared either with some antigen that 

 is known to give good results or with the following approximate 

 color standard : 



1. A solution is prepared containing 0.5 gm. potassium 

 bichromate (K 2 Cr 2 0 7 ) in 100 c.c. distilled water (permanent 

 standard solution). 



2. One c.c. of this solution is mixed with 75 c.c. distilled water. 



3. Ten c.c. of solution 2 is measured into a tube of the same 

 size containing the extract to be tested and the colors compared. 



If the amount of coloring matter in the new extract is weaker 

 than in the standard, room temperature or incubator temperature 

 for some hours or overnight may be resorted to until coloring 

 matter is brought up to that contained in the standard. If the 



7 J. Kans. State Med. Ass'n, 1923, xxiii, 4. 



