Cultivation 



423 



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 exam- 

 ined. If the diphtheria bacillus be present, a smeary, 

 yellowish- white layer will be present upon the first tube, a 

 similar layer with outlying colonies on the second tube, 

 while the third tube will show rather 

 large, isolated, whitish or slightly 

 yellowish, smooth colonies. The 

 colonies may be china-white in ap- 

 pearance. These colonies, if found 

 by microscopic examination to be 

 made up of diphtheria bacilli, will 

 confirm the diagnosis of diphtheria, 

 and will at the same time give 

 pure cultures of the bacillus when 

 transplanted. There are very few 

 other bacilli that grow so rapidly 

 upon LofHer's mixture, and scarcely 

 any other is found in the throat. 



When no tubes of the blood- 

 serum mixture are at hand, the 

 swab can be returned to its tube 

 after having been wiped over the 

 throat of the patient, and can be 

 shipped to the nearest laboratory. 



When an early diagnosis is re- 

 quired, Ohlmacher recommends 

 that the microscopic examination 

 of the still invisible growth be made 

 in five hours. A platinum loop is 

 rubbed over the inoculated surface ; 

 the small amount of material thus 

 secured is mixed with distilled 

 water, spread on a cover-glass, 

 dried, fixed, stained with methy- 

 lene-blue, and examined. An abun- 

 dance of the organisms are usually 

 found and valuable time is saved preparatory to the use of 

 the antitoxin. 



The presence of diphtheria bacilli in material taken from 

 the throat does not necessarily mean that the person has 



Fig. 125 Sterilized 

 test-tube and swab for 

 collecting pus and fluids 

 for bacteriologic examina- 

 tion (Warren). 



