Bacteriologic Diagnosis 



443 



until cultures made from their throats show that the bacilli have 

 disappeared. 



Bacteriologic Diagnosis.— It is impossible to make an accurate 

 diagnosis of diphtheria without a bacteriologic examination. 



Such an examination is now within the power of every physician. 

 All that is required is a swab made by wrapping a little absorbent 

 cotton about the end of a piece of wire and carefully sterilizing it 

 in a test-tube, and a tube of LofHer's blood-serum-medium. These 

 are now commonly provided 

 free of charge by state and 

 municipal health boards or if 

 desired, can be bought from 

 almost any modern druggist. 

 The swab is introduced into 

 the throat and applied to the 

 false membrane, after which 

 it is carefully smeared over 

 the surface of the blood- 

 serum. The tube thus in- 

 oculated is stood away in an 

 incubating oven or other- 

 wise kept at the temper- 

 ature of 37°C. for twelve 

 hours, then examined. If 

 the diphtheria bacillus be 

 present, a smeary, creamy- 

 white layer with outlying 

 colonies will be present. 

 These colonies, if found by 

 microscopic examination to he 

 made up of diphtheria bacilli, 

 will confirm the diagnosis 

 of diphtheria. There are 

 very few other bacilli that 

 grow so rapidly upon 

 Loffler'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 required, 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 mi?ced with distilled 

 water, spread on a cover -glass, dried, fix:ed, stained with methylene 

 blue, and examined. An abundance of the organisms is usually 



Fig. 157. — The Providence Health De- 

 partment outfit for diphtheria diagnosis, 

 consisting of a pasteboard box containing 

 a swab-tube and a serum-tube, both with 

 etched surface on which to write the name 

 and address of patients, etc. 



