BIOf.OGI(L\L AND ANTKIRNIC Sl'KCIFICITY 325 



Euglena (jmcilis Klehs is not a homogeneous group but consists 

 of two distinct antigenic types. Tliese correlate with growth 

 characteristics. 



Antigens in Fungi. — Hektoen (1901) noted antigenic properties 

 for a strain of Blastomyces dermatitis. Recently Dnlaney (1930) 

 confirmed this work, but could not demonstrate species specificity 

 in the blastomyces. She says that "slightly positive results were 

 obtained with closely related yeasts and specific results were ob- 

 tained upon titration of the serums. ' ' 



In this connection it is interesting to note that IMueller and 

 Tomesik (1924) obtained a soluble specific substance from yeast 

 and found it to l)e identical With the "yeast gum" of Salkowski 

 (1894). It yielded specific precipitates with homologous immune 

 serum but was found to be nonantigenie. This work has been ex- 

 tended recently by Tomesik (1930). Kesten, Cook, Mott, and 

 Jobling (1930, 1931) liave isolated s])oeific i)olysaccharides from 

 strains of monilia. 



Bacterial Antigens. — While this subject will ])e discussed in 

 Chapter XIX, attention can be called here to the fact that they, 

 like the algae, fungi, amebae and red blood cori:)uscles, represent 

 cellular or protoplasmic antigens exceedingly complex in nature 

 and in which haptens play an important role in the serological re- 

 actions. By agglutination and absorption tests it has been possible 

 to demonstrate species specificity for some species, e.g., E. typhosa 

 while for others like Esch. coli only strain specificity has been 

 demonstrated as yet. 



Only a small amount of albumin or globulin has been found in 

 the bacterial extracts, the bacterial cell substance containing for 

 the most part nucleoproteins. A continuation of the study of 

 bacterial proteins such as the P^ and F^ fractions obtained by 

 Furth and Landsteiner and of the cell haptens gives promise of 

 a better understanding of bacterial antigenic specificity. 



Structure and Properties of Proteins. — When one looks at the 

 lU'oteins from the standpoint of their chemical structure and 

 biochemical pro])erties, one discovers a number of reasons why 

 most antigens are probably protein in nature and how their struc- 



