31 
J. A. Arkwright, E. E. Atkin and A. Bacot 
former being more common. This was also the case in smears of unhatched 
bugs extracted from the egg. Smears of eggs showing the early developmental 
stage of the bug (as a rule these eggs have to be dissected out of the ovarv 
or made into smears soon after laving), contain immense numbers of more or 
less well-stained granules, usually poorly defined, but in some cases of distinct 
Rickettsia form and sharp in outline (Plate II, fig. 7); this feature may 
characterise the greater part of the smear. More frequently, however, it is 
confined to small patches in what are otherwise areas of ill-defined granules. 
Since we failed to cultivate the organism we cannot tell whether the ill- 
defined granules are related to the parasite or whether they are merely 
particles of protein. The sharply outlined forms are, we believe, undoubtedly 
a stage in the life-cycle of the organism. The minute bacillary forms that are 
present among the coccal and diplococcal forms are much more numerous in 
some smears than in others./ Smears of the guts of embryo bugs at a late 
stage of development extracted from the egg, in some cases show masses of 
the minute forms deeply stained and clearly defined, lying within the lumen 
of the gut, where they have presumably been isolated as a part of the detritus 
of the embryonic process. 
In order to obtain additional proof of hereditary infection, ovaries were 
dissected out of females that had been washed in lysol and then in sterile 
salt solution. Smears made from eggs extracted from these ovaries usually 
showed a few threads with some admixture of the shorter bacillary forms in 
addition to the granular infection alluded to above. 
Intracellular multiplication and development. 
Apart from its presence in the undifferentiated egg mass, the development 
of the parasite seems to be entirely intracellular. No evidence has been 
obtained of its multiplication in the lumen of the gut or in the body cavity 
where, however, thread forms have been found. Smears of teased embryos 
taken from developing eggs and of various organs from older bugs including 
the ovaries, testes, organ of Berlese and Malpighian tubes show minute coccal, 
diplococcal and lanceolate forms. These latter are slightly larger than the 
coccal and diplococcal (Rickettsia) forms and stain red instead of purple. 
Clusters of these red staining forms (Plate II, fig. 1), sometimes accompanied 
by a few of the Rickettsia forms, occur in the cytoplasm. They are best ob¬ 
served, individually, when the infected cell has been ruptured in such a 
manner as to spread its contents without breaking its nucleus. Very many 
examples of intermediate forms between these bodies and the longer bacterial 
forms have been observed; some clusters showed the lanceolate forms together 
with their various stages of growth into rods (Plate II, fig. 3). The inter¬ 
mediate forms were very often curved. Growth of the rods into threads is 
shown in almost every smear but apparently only in the enlarged cells of the 
Malpighian tubes do the threads attain their full length (Plate II, fig. 8). 
