30 FREDERICK EBERSON , 



bacteriologc study of body fluids and glands and of secondary invaders 

 in Common diseases will undoubtedly give us material for ultimate 

 classification. Apart from Morse's biometric study of the diphtheria 

 group, no other classification has been presented. In the light of the 

 material given here it seems as if Morse's classification on the basis of 

 chromogenesis, vigor of growth and fermentative properties is not 

 entirely adapted to the great number of strains which have already been 

 described and which are forthcoming. Serologic studies as a means of 

 classification in this group of bacteria have not been worked out suffi- 

 ciently to merit much discussion; the little work done has not been of a 

 very searching nature. It seems that here are the most promising 

 possibilities. Agglutination has been tried by Nicholas, Nicolle, Land- 

 steiner, Bruno, Lubowski, Lesieur, and Fraenkel with varying results, 

 which were not specific. The consensus of opinion seems to be that 

 the organisms do not produce agglutinating substances in the serum. 

 Complement fixation has not been sufficiently studied. The results of 

 Morse show that cross-reactions may be obtained for the diphtheroid 

 antigens and that C. diphtheriae does not fix with any of the diph- 

 theroid antigens. The results, however, are not striking enough to be 

 conclusive. The method of preparing antigen undoubtedly will modify 

 the results in such tests. Ground bacteria were used and specific serum 

 obtained by the injection of formalized suspensions of whole organ- 

 isms. Perhaps Olitzky's method for complement fixation in typhus 

 fever, would be preferable. According to his technic, nonspecific fixa- 

 tion is prevented by the use of Berkefeld filtrates of autolyzed bacteria. 

 It is hoped that by means of group reactions the diphtheroids may be 

 classified definitely. Precipitation tests suggest good possibilities. The 

 reaction is exceedingly delicate and the organisms lend themselves to 

 ready disintegration and extraction. 



II. SEROLOGICAL 



EXPERIMENTS WITH HODGKIN^S STRAINS 



In order to determine the identity of cultures isolated from cases of 

 Hodgkin's disease, two methods were utilized agglutination and com- 

 plement fixation. The first method enables us to identify the specifi- 

 city of the organisms by means of serums obtained from patients suf- 

 fering with the disease as well as by serums prepared with the different 

 strains of bacteria isolated. Obviously, if the C. Hodgkinii is the cause 



