N. H. SWELLENGREBEL 
475 
especially so because the base of the flagellum becomes often very 
indistinct. Many dividing granules are to be observed which often 
look very regular and suggest a “ reduction ” of the blephai’oplast (figs. 
5, 6, 8, 9) or even mitotic spindles are simulated (fig. 10). Some¬ 
times the blepharoplast, and with it the flagellum, wanders in the 
direction of the nucleus (fig. 9), but a real crithidia facies is never 
produced. In other cases the products of hypertrophy and division of 
the blepharoplast are less regular and take the shape of achromatic 
reticula with chromatic granules distributed over it (fig. 11). All these 
changes may be produced on a much larger scale, large masses of 
chromatic and achromatic substance being formed (figs. 12, 13) or long 
chromatic strings being loosened from the degenerating blepharoplast 
(figs. 14, 15). Some of these chromidia, as they may correctly be 
named, wander towards the nucleus, so repeating on a large scale 
Moore, Breinl and Hindle’s “autogamy.” 
Many of the changes of the blepharoplast described here bear a 
marked resemblance to the reduction of the blepharoplast during the 
parthenogene.sis seen by Prowazek in cultures, and previous to copula¬ 
tion in the gut of Ilaematopinus. I think all these phenomena do not 
belong to the normal life cycle of T. leivisi. As in the blepharoplasts 
of fig. 3 (Diagram II) the distinction of chromatic and achromatic sub¬ 
stance is well marked in these degenerating blepharoplasts. 
{h) Changes of the nucleus. (Diagram XIV.) The nucleus becomes 
first enlai’ged and the karyosome becomes often elongated as during a 
division (fig. 1) ; then it becomes larger and seems to absorb all the 
chi’omatin, the rest of the nucleus becomes pale and indistinct (fig. 2). 
The karyosome becomes longer and takes the shape of a twisted filament, 
the rest of the nucleus becoming indistinct (fig. 7) and disappears at 
last (fig. 8), so that instead of a nucleus there appears a filament, wound 
in the form of a spiral or zigzag line (figs. 9, 14) closely resembling 
Prowazek’s “ male ” form. 
In other cases the chromatin may be expelled from the nucleus 
(fig. 3) in the form of one or more granules or irregularly shaped masses 
(figs. 4—6). These forms correspond to the stages of nuclear reduction 
in the rat’s blood and in the louse’s gut as described by Prowazek. If 
these were the only stages to be found, this supposition might be 
possible, but the formation of chromidia continues (fig. 10), the nucleus 
becoming pycnotic at the same time. At last only some dumb-bell 
shaped rodlets are to be found and when the blepharoplast is broken up 
at the same time (which is not always the case), the cell is filled with 
Parasitology iii 
31 
