SACBEOOD. 49 



lively small quantity of more or less clear liquid. The scales formed 

 by the drying of the decaying remains are easily removed from the 

 cells. After becoming quite dry many of them indeed can be shaken 

 from the brood comb. 



Upon crushing larvae which have been found dead for some time but 

 not yet diy, a marked unpleasant odor will be noticed if the crushed 

 mass is held near the nostrils. 



Microscopically no microorganisms are to be found in the decay- 

 ing remains of the larvae. Cultures made from them are also neg- 

 ative. 



Differential diagnosis. — Sacbrood must be differentiated from the 

 other brood diseases. 



American foulbrood may be recognized by the peculiar odor of the 

 brood combs when the odor is present. The body wall of the larval 

 and pupal remains is easily ruptured, and the decaying mass becomes 

 viscid, giving the appearance popularly referred to as "ropiness." 

 The scale adheres quite firmly to the floor of the cell. The presence 

 of BaciUus larvse in the brood dead of the disease is a positive means 

 by which it may be differentiated from sacbrood. 



European foulbrood may be recognized by the fact that the larvae 

 as a rule die while coiled in the cell and before an endwise position is 

 assumed. In the majority of instances, therefore, death takes place 

 before the cells are capped. The saolike appearance characterizing 

 the dead larvae in sacbrood is absent. The granular consistency of 

 the decaying mass is absent also. Microscopically, a large number of 

 bacteria are found in larvae dead of European foulbrood, but are 

 absent in larvae dead of sacbrood. The presence of BaciUus platan 

 is a positive means by which European foulbrood may be recognized. 

 BaciUus alvei and other species may also be present. 



Sacbrood must also be differentiated from other conditions re- 

 ferred to as chilled brood, overheated brood, and starved brood, 

 which occasionally are encountered. This can be done by a compar- 

 ison of the symptoms presented by these different conditions with the 

 symptoms of sacbrood, and the history of the cases. Some of the 

 larvae dead from these conditions will be found to have died while 

 yo.t coiled in the c(ill. This fact suggests some condition other than 

 sacbrood. When dying later, the saclike remains characterizing sac- 

 }>rof)(] iiTc not present in conditions other than sacbrood. 



PROGNOSIS. 



The tendency in a colony afi"(H't<ul witli sacbrood is to recover from 

 \\\o. (lis(ias<i. (/oloiiies vvliich cliii-ing (he spritig niontlis show the |)r<is- 

 ciicd of moid or loss disease, hy iriidsuminer or (uirH(U' may, and ve.i-y 



