158 IMMUNOLOGY 



and Ecker (1941) have made an extensive study of the endpieee in- 

 eluding the fourth component of complement. They say that their 

 findings ''seem to indicate that the endpieee of complement is the 

 calcium-carbohydrate-pseudoglobulin molecule" and that in the 

 light of this "the fourth component would be the carbohydrate." 

 They consider that the complex calcium-pseudoglobulin molecule 

 is the carrier of the active carbohydrate factor. If their work is 

 confirmed, the old conception of endpieee as an albumin will have 

 to be abandoned. 



In another paper Ecker, Jones and Kuehn (1941) suggest that 

 the euglobulin fraction of midpiece is closely associated with a 

 phosphatide (cephalin). The importance of this observation is 

 apparently unknown. Sensitized cells which have adsorbed the 

 globulin fraction (midpiece) only are called ''per sensitized" cells. 



Preservation of Complement. — When serum rich in comple- 

 ment is frozen, its potency as a lytic agent of sensitized cells is re- 

 tained for one or more weeks. Kolmer suggests that this is prob- 

 ably the oldest method of preserving complement. Morgenroth 

 and others were able to preserve complement kept at -10 to -15° 

 C. for several weeks. Kolmer found that either diluted or un- 

 diluted complement kept frozen except when samples are removed 

 retains its titer undiminished for 3 or 4 days, after which time it 

 drops rather rapidly. The titer of undiluted complement kept at 

 4° to 9° C. is diminished in 24 hours, and shows progressive 

 deterioration thereafter. 



Many laboratories preserve complement by freezing and desicca- 

 tion in vacuo at a low temperature. This method has come into 

 rather general use since the publication of Flosdorf and Mudd 

 (1935, 1938) in which they describe the procedure and apparatus 

 that operates successfully. The methods are applicable to the 

 ])reservation of various kinds of immune sera and also bacteria. 

 The first method depended largely upon the vacuum pump for 

 removal of the water vapor given off during drying and the dried 

 serum was called "lyophile" serum. In 1938 the same authors 

 reported upon a simpler and better method of desiccation. In this 

 method both chemical desiccants and physical evacuation were 

 used. The method is called the Cryo-chem process. Complement 

 preserved by this method is stored in the refrigerator and main- 

 tains its titer for long periods of time. 



