DIPHTHEROIDS Io y 



mediate diagnosis is possible in probably 35% of cases by making a smear from a 

 piece of membrane. In doing this Neisser's stain or the toluidin blue stain are 

 usually considered the most satisfactory. I prefer the Gram stain, however. The 

 diphtheria bacilli found in such smears are not apt to be clubbed and stain more 

 uniformly. 



If there is any doubt about the nature of an organism in a throat culture, always 

 stain: i. with Loffler's alkaline methylene blue for two minutes; 2. with Gram's 

 method, being careful not to carry the decolorization too far, and 3. by Neisser's 

 method. With Loffler's you obtain a picture which, after a little experience, is 

 characteristic; at times the polar bodies show as intense blue spots in the lighter 

 blue bacillus. One is liable to confuse cocci lying side by side for diphtheria bacilli 

 with segmental or banded staining. This difficulty is not apparent when Gram's 

 staining is used. This gives us great information, as the diphtheria and the pseudo- 

 diphtheria are the only small Gram-positive bacilli usually found in the mouth. 

 The cocci are also well brought out. Neisser's stain gives a picture which, when 

 satisfactory, is almost absolutely characteristic. You have the bright blue dots 

 lying at either end of the light brownish-yellow rods. When first isolated from a 

 throat, the diphtheria bacillus is apt to stain characteristically by Neisser. Later 

 on, in subculture, there may be no staining of the polar bodies. Neisser originally 

 recommended five seconds' application, with an intermediate washing, for each of 

 his two solutions. Thirty seconds for each is probably preferable. Some authorities 

 recommend five to thirty minutes. It is well to bear in mind that about 2% of the 

 people in apparent health carry diphtheria bacilli of the granular or barred type in 

 their throats and of these about one in five will prove virulent for the guinea-pig. 



It is essential when a question exists as to the nature of a diphtheria- 

 like organism to test it as to virulence. While there are exceptions, 

 especially in freshly isolated colonies, yet as a rule a severe infection 

 yields virulent organisms and vice versa. Pure cultures are best ob- 

 tained by streaking material from the throat on glycerine agar plates. 

 From an isolated colony inoculate a tube of bouillon. From such a forty- 

 eight- or seventy-two-hour-old culture inoculate a guinea-pig with 2 or 3 

 drops subcutaneously in the shaven abdomen. Escherich considers a 

 fatal result with 1.5 c.c. of such a bouillon culture a satisfactory test as to 

 virulence. After death, which occurs in two or three days, the adrenals 

 are enlarged and haemorrhagic. The diagnosis is more sure if, in addi- 

 tion to the first animal, a second one, which has had antitoxin, is inocu- 

 lated. The protected one should live. 



Diphtheroid Bacilli. Pseudodiphtheria Bacillus. Hofmann's Bacil- 

 lus. Under these terms various Gram-positive bacilli have been de- 

 scribed as occurring in genito-urinary, nasal and skin diseases. 



Their chief importance is in connection with their presence in the 

 throats of healthy people. Probably approximately 10% of people 

 harbor such organisms as against i to 2% with granule types. Some 



