16 BULLETIN 809, U. S. DEPARTMENT OF AGRICULTURE. 



number of rods. A partial explanation at least of this rather unex- 

 pected fact was gathered from the study of the organism on artificial 

 media. Here it was found that the rods at times undergo interesting 

 but as yet undetermined changes. On glucose and other media, 

 when the growth is luxuriant and the spore formation is very much 

 inhibited, it is noted that in older cultures rods are comparatively 

 few in number but in their stead are forms which are neither rods nor 

 spores but are small, more or less spherical bodies (PL VII, F, G, H). 

 The exact transformation that has taken place in the bacillus to 

 produce these bodies is not known. Something of the phenomenon 

 has been learned through a study of the rods stained with a flagellar 

 stain employing in the method a light aqueous suspension of a young 

 culture. In such preparations there is seen within the rods a number 

 of individual elements, apparently, each of which is supplied with 

 flagella. These structures become independent and separate from 

 the rod proper (fig. 5; PI. VII, E, F, G, H). In the cultures are 

 found also, especially in the condensation water of brood-filtrate-agar 

 slant cultures (PI. VIII, D), giant whips (fig. 6; PL VII, F, G, H) 

 of various sizes. That the little-understood changes that take place 

 in the vegetative forms bear a close relation to the formation of the 

 giant whips can readily be suspected. 



Definite data have been sought to prove the identity of the ropy 

 foulbrood of the different countries. Samples of brood comb con- 

 taining disease material were received from Canada, Cuba, England, 

 France, Germany, New Zealand, and Switzerland. The findings from 

 studies made on these were compared each with the other and with 

 the findings from many samples from the United States. Spores of 

 Bacillus larvae in very large numbers and practically in pure cultures 

 were present in every one. In each instance one of the special 

 media (p. 18, 19) required for the cultivation of this species was 

 needed. Culturally the bacillus was the same from all of the 

 samples. The disease produced by the inoculation of colonies of 

 bees was also similar in every instance. Sera from rabbits im- 

 munized with cultures from American sources agglutinated in high 

 dilutions cultures from English, New Zealand, and Switzerland 

 sources at least, these being all that were tested in this way. The 

 evidence, therefore, justifies the conclusion that the ropy foul- 

 brood of each of the different countries mentioned above is identi- 

 cally the same disease. 



Four rabbits inoculated with pure cultures of Bacillus larvae showed 

 comparatively little reaction. In each instance there was used a 

 moderately clouded suspension in normal salt solution made from the 

 surface of the brood-filtrate-agar slant culture about 24 hours old. 

 Two of them were inoculated subcutaneously with 1 and 2 c. c. 

 of the suspension, respectively; one received the culture intraperi- 



