3 o8 



CHARLES T. BRUES AND RUDOLPH W. GLASER. 



velop almost equally well in the greatly diverse concentrations 

 of sugar and in the plain potato agar. A microscopic examina- 

 tion at this time showed that nearly all the tubes in which growths 

 occurred contained the same microorganism, and that only a few 

 were contaminated by molds (PemcilUum) and bacteria. The 

 abundant species showed large numbers of budding yeast cells 

 like those in the living scale insects and the development of my- 

 celium as well showing that the symbiont was a fungus and not a 

 yeast as one might otherwise be led to believe from a study of the 

 living insects, at this season of the year when only single budding 

 cells occur in the fat body. 



Several of the colonies thus obtained were plated, found to be 

 pure and sub-cultures were then made from these which have 

 furnished the material for the description and cultural characters 

 detailed below. Although the morphology of the organism in the 

 living insects and in the cultures and the fact that it was recovered 

 in such a large proportion of the cultures, left little doubt as to 

 the identity of the two, we undertook some serological tests to 

 corroborate if possible the conclusion based on morphological 

 data. 



For this purpose, two rabbits were secured, inoculated with 

 bouillon cultures of the fungus, and serum from each was tested 

 with the cultures and also with the organisms in the living scale 

 insects. The following table shows the doses used and the reac- 

 tions of the rabbits. 



One week later some blood was withdrawn from each rabbit 

 and serum prepared. A precipitin test with the culture gave a 

 positive reaction after four hours, and agglutination was very 

 pronounced after one and one half hours as examined under the 

 microscope. On account of the impossibility of securing suf- 

 ficient material from the living scales, it was possible to try with 



