SACBEOOD. 



29 



In the study of the virus of sacbrood use has been made also of 

 the Pasteur-Chamberland filter ^ (fig. 27). This is a clay filter, the 

 pores of which are much finer than those of the Berkefeld used. In 

 using this filter, an aqueous suspension of la.rvse dead of the disease 

 is prepared as before. This is filtered by the aid of pressure obtained 



Fig. 27. — A convenifint apparatus wliiuh cau bo employed in using the Pasteur-Chamborland, 

 Berkefeld, and other filters. Pasteur-Chamberland filter (b) with a glass mantle (a), a rubber stopper (c) 

 through whifth passes the filter, a connecting rubber tubing (d), glass tubing (e), a perforated rubber 

 stopper (f), a vacuum jar (g), designed by the writer, in which is placed a cotton-stoppered and steril- 

 iVd flask, a glass stopcock (h), a vacuum gauge (i), a reservoir (m) with pressure-rubber connections 

 (j;, and a vacuum pump (k). (Original.) 



by means of a partial vacuum in an apparatus devised for this pur- 

 pose. Filtrates obtained from this filt(T wh(!n fed to healthy coloui<>s 

 produced the disease. Since the virus of sacbrood wiU pass through 



'The Pastenr-f'hamberland filter consists of clay molded in the form of a hollow cylinder and baked. 

 ThI.s Is used with a glass cylinder (a) fitted with a rubber stopper (c). In the use of this filter, force is 

 employed. Thi.s was obtained for these experiments through the use of a jar (g) devised by the writer in 

 which a fmrtial vacinim can be prfHluwd. in thi.s jar, is placed a tlask plugged with cotton and sterilized. 

 f(»nn<>ctions are made as shown in the illustration, the vacinim being produced through the use of the 

 pump fk). In less than half an hour usually a half-|)int of filtrate can be obtained with this apparatus. 



