THE CAUSE OF EUROPEAN FOUL BROOD. 7 



insj)ection this intestinal mass appears Avhite or yellowish white, the 

 presence of European foul brood is almost certain. A modification 

 of this simple inspection method maj^ often be profitably used. This 

 consists simply in turning the larva in the cell with a pair of forceps 

 until the median dorsal line is exposed to the observer. 



More frequently still, it will be found advantageous to remove the 

 larva from the cell with the forceps. With a little care this can be 

 done, leaving the larva intact. If the larva is diseased and the dis- 

 ease is sufficiently advanced, a Avhitish intestinal content can very 

 often be plainly observed. In response to the muscular action of the 

 larva this mass is frequently seen to be moved to and fro. 



A POSITIVE TEST FOR THE DISEASE IN LIVING LARV^. 



There is a sign represented in figure 8 which, in the experience 

 of the writer, has proven thus far to be a positive symptom of Euro- 

 pean foul brood. Allien the age and condition of the diseased lar^^a 

 are favorable — and these frequenth' are — the sign can be quite 

 easily and conveniently demonstrated in this way: Select a larva to 

 be tested, approximately of the age represented by figures 2. 3, and 4 ; 

 remove it from the cell and place it upon glass, preferably with a 

 dark background; with a dissecting needle in each hand and with 

 their points near together, pierce Avith both needles the wall of the 

 larva near its head, avoiding the intestine; separate now the points 

 of the needles so as to tear the body wall crosswise and continue to 

 separate the two portions of the larva. If the larva is diseased and 

 one is successful in applying the test, it will be found that the in- 

 testinal content will be stripped from and pulled out of the posterior 

 and blind end (5, fig. 10) of the canal, obtaining results as repre- 

 sented in figure 8. In case of living, healthy larv?e the intestinal 

 content can not be removed in this way. 



This mass thus removed from the intestine, if examined micro- 

 scopically, will be found, in general, to consist of a white or slightly 

 yellowish-Avhite mass along the longitudinal axis. This central mass 

 is surrounded by a substance which is more or less transparent and 

 mucuslike in appearance. The appearance of this outer portion, 

 however, will vary in detail, depending in a great measure upon the 

 stage of the disease when the examination is made. 



The force which is applied in pulling the mass from the intestine 

 frequently causes this enveloping substance to stretch and the in- 

 closed whitish substance to break into segments as represented in a 

 of figure 8. This is an earlier stage of the disease than that repre- 

 sented in either h or c of the same figure. 

 38171°— Cir. 157—12 2 



