EMMERICH'S METHOD 99 



the cap is again put on, and, by blowing air through the 

 lateral tube which was connected with the aspirator, the 

 fluid is driven up into the vertical one, so as to wash it out. 

 Finally the point of the glass tube on the opposite side is 

 broken off, and the fluid contained in the flask distributed 

 into tubes of bouillon. 



Emmericli's method. — In the apparatus devised by Em- 

 merich for bacteriological research of this nature, the air 

 is drawn slowly through a coiled tube filled with nutrient 

 bouillon, and the germs are in this manner retained (fig 30) . 



Aspirator tube 



Plug of cotton wool 



Coiled tube containing 

 nutrient bouillon 



Fig. 30. — Emmerich's Apparatus for EXAMiNixa Aiit. 



Welz's method, — Two small flasks, one as a receiver, 

 and the other as a control flask, are prepared with 20 c.cm. 

 each of a neutral liquid composed of equal parts of glycerine, 

 bouillon, and water, and are connected together by means 

 of a glass tube bent twice at right angles, the longer limb of 

 which reaches to the bottom of the control flask, the shorter 

 to just below the stopper of the receiving flask. Two large 

 flasks connected by means of a rubber tube are used for 

 aspirating, one being filled with water and united to the 

 controlling flask. The other, which is empty, stands at a 

 lower level than that containing the water, so that this 



H 2 



