DIPHTHERIA. 223 



When it is desired to make a bacteriologic diagnosis 

 of a suspected case of diphtheria or to secure the bacillus 

 in pure culture, a sterile platinum wire having a small 

 loop at the end, or a swab made by wrapping a little 

 cotton around the end of a piece of wire and carefully 

 sterilizing in a test-tube, is introduced into the throat 

 and touched to the false membrane, after which it is 

 smeared carefully over the surface of at least three of 

 the blood-serum-mixture tubes, without either again 

 touching the throat or being sterilized. The tubes thus 

 inoculated are stood away in an incubating oven at the 

 temperature of 37 C. for twelve hours, then examined. 

 If the diphtheria bacillus is present upon the first and 

 second tubes, there will be a smeary yellowish-white layer, 

 with outlying colonies on the second tube, while the third 

 tube will show rather large isolated whitish or slightly 

 yellowish colonies, smooth in appearance, but rather ir- 

 regular in outline. Very often the colonies are china- 

 white in appearance. These colonies, if found by micro- 

 scopic examination to be made up of diphtheria bacilli, 

 will confirm the diagnosis of diphtheria, and will at the 

 same time give pure cultures when transplanted. There 

 are very few other bacilli which grow so rapidly upon 

 LofHer's mixture, and scarcely one other which is found 

 in the throat. 



Ohlmacher recommends the microscopic examination 

 of the still invisible growth in five hours. A platinum 

 loop is rubbed over the inoculated surface ; the material 

 secured is then mixed with distilled water, dried on a 

 cover-glass, stained with methylene blue, and examined. 

 This method, if reliable, will be very valuable in making 

 an early diagnosis preparatory to the use of the antitoxin. 



The presence of diphtheria bacilli in material taken 

 from the throat does not necessarily prove the patient to 

 be diseased. Virulent bacilli can often be discovered in 

 the throats of healthy persons who have knowingly or 

 unknowingly come in contact with the disease. The 

 bacteriologic examination is only an adjunct to the 



