PATHOGENIC BACTERIA. 



28l 



FIG. 78. 



what in detail, but are similar in the main, and are based 

 upon the procedure devised by Biggs and Park for the 

 Board of Health of New York City. Two tubes are fur- 

 nished in a box. The tubes are like ordinary test-tubes, 

 about three inches in length, rather 

 heavy, and without a flange. Both are 

 plugged with cotton. One contains slant- 

 ed and sterilized Loffler's blood-serum 

 mixture; the other contains a steel rod, 

 around the lower end of which a pledget 

 of absorbent cotton has been wound and 

 the tube afterward sterilized. The swab 

 is wiped over the suspected region in 

 the throat, taking care that it touches 

 nothing else, and is then rubbed over the 

 surface of the blood-serum mixture. The 

 swab is returned to its test-tube and the 

 cotton plugs are returned to their respec- 

 tive tubes. The plugs, of course, are held 

 in the fingers during the operation, and 

 care must be taken that the portion of the 

 plug thatgoes into the tube touches neither tube us f;. n , th . c 



nosis of diphtheria. 



the finger nor any other object. The prin- 

 ciples, in fact, are the same as those laid down in general for 

 the inoculation of culture-tubes with bacteria (see page 84). 

 In board of health work these tubes are returned to the 

 office. When it is desirable, a second tube may be inoculated 

 from the swab. The tubes are placed in the incubator, 

 where they remain for from twelve to twenty-four hours, 

 and a microscopical examination is then made of smear pre- 

 parations stained with Loffler's methylene-blue. On Loffler's 

 blood-serum kept in the incubator the bacillus of diphtheria 

 grows more rapidly than the other organisms which are ordi- 

 narily encountered in the throat, a property which to a cer- 

 tain extent sifts it out, as it were, from them, and makes its 



Swab and culture- 



