IMPORTANCE OF ANTIBODIES IN DIAGxNOSIS 395 



The second reason is to enable the clinician to make a more ac- 

 curate prognosis and to have available accurate hospital records 

 for future reference in regard to the prevalence of the various 

 types, etc. Studies such as those of Avery, Chickering, Cole and 

 Dochez (1917) are ample evidence of the importance of such a 

 procedure. Tlie third reason is that all research projects such as 

 thase of Avery and Goebcl (1931), Heidelberger (1926) and others 

 require accurate typing of the ])neumococci with which they are 

 working. 



Technique. — The teclmical procedures used in specific type 

 determination were first suggested by Blake (1917) and Avery 

 (1917). They consisted of a rapid method using calcium carbonate 

 bloodbroth and the mouse method for agglutination and precipita- 

 tion. 



The quellung reaction has to a large extent replaced the ag- 

 glutination and precipitation techniques. It is used either for the 

 direct examination of spinal fluid, pleural exudates, in fresh 

 sputum, or in connection with the mouse and cultural methods. 

 When used to examine the peritoneal inflammatory exudates of 

 mice inoculated with positive sputum, the quellung reaction gives 

 excellent results. 



Neufeld's Quellung Reaction. — In 1902 Neufield reported that 

 when specific immune serum is mixed with pneumococci, in the 

 fresh state, there results not only agglutination but also a swelling 

 (quellung) and the development of a ground glass appear- 

 ance of the peripheral zone of the organisms. He added methylene 

 blue to the mixture to stain the organisms. In 1932 Arm- 

 strong and also Logan and Smeall, using a slightly diiferent 

 technique, reported excellent results in typing. Their technique 

 was found unsatisfactory by Sabin who reports excellent results 

 with the Neufcld procedure. The latter was demonstrated to Sabin 

 by (loodner. While the method is simple, rapid, and apparently 

 accurate, it is obvious that the observer must l)c a good micros- 

 copist. Sabin 's description of the technique is as follows: 



Sahin's Description of Neufeld's Method. — "Two small flecks of 

 sputum are placed on a cover sli}) (about 22 by 50 mm.) with a 

 platinum loop, the diameter of which preferably does not exceed 

 2 mm. When the sputum is very tenacious, as it frequently is, it 



