Contagious Diseases of Insects. 299 



ticular from the original. Singles occurred occasionally, but 

 most of the specimens were in doubles, no chains being noticed. 



Additional slides, mounted October 2, show likewise the 

 same spherical Micrococcus without admixture, or change in 

 size or mode of aggregation ; and still another series mounted 

 from the same tubes, April 9, 1884, represent a still pure cul- 

 ture of what was probably this same Micrococcus. The speci- 

 mens differ only by the somewhat smaller size, rarely surpassing 

 .8 ft, a difference probably to be accounted for by an exhaus- 

 tion of the nutritive fluids, certain to have occurred during the 

 seven months which had elapsed since the culture was begun. 

 It should be said, also, that the slides of this last stage are less 

 distinctly stained than the preceding, the micrococci very prob- 

 ably being dead. 



After a careful re-examination of these materials I do not 

 doubt that this was a successful culture of the spherical Micro- 

 coccus, preserved through the winter, practically unaltered, in 

 a test tube plugged with cotton. It should be added that the 

 check tube remained throughout unchanged. 



An interesting culture was begun September 8, the 

 material being obtained from a larva of Datana ministra dead 

 several hours. The slides representing this larva are impure, 

 the fluids from the alimentary canal containing not only 

 spherical micrococci, but also a few ovals, and great numbers of 

 bacilli. The spherical micrococci range in diameter from 1 ^ 

 to 1.25 A*, and are occasionally indistinctly quadrate, especially 

 when occurring in chaplets (as they frequently do). A few 

 doubles measure 3 t*. The bacilli are all slender, varying 

 greatly in length (from 3 ^ to 5 ^), but all .7 /* in transverse 

 diameter. 



The beef broth infected with this material on the 8th 

 September was observed on the 15th to have become slightly 

 milky, and, examined, was found to contain micrococci in 

 couples and chaplets, chiefly arranged in the latter form. The 

 slides made from this culture contain no bacilli, but only 

 spherical or subquadrate micrococci in doubles and strings. 

 These average a scant micro in diameter, some, however, reach- 

 ing 1.25 ^. October 2 these fluids were found to contain only 

 the same Micrococcus, not distinguishable in any way from 



