﻿88 MIYAJIMA. 



number of the pyriform bodies in the material treated renders the work 

 most difficult and on the other, when a flagellate once starts to develop 

 in the culture, it multiplies so quickly as very much to interfere with the 

 work of tracing each developmental stage. After extensive researches, 

 certain interesting forms of the parasites were found in the stained 

 films prepared from young cultures, which afterwards gave a growth of 

 numerous trypanosomata. Soon after the culture was made, a few round 

 cells, which morphologically were identical with the free pyriform bodies, 

 were seen in stained preparations. (PI. I, fig. 2.) Within the first 

 twenty-four hours after incubation, the diameter of the round cells 

 (PL I, fig. 3) increased, and it finally became twice that of an erythro- 

 cyte. Associated with the enlarged cells there also were irregular amoe- 

 boid forms (PL I, fig. 4) similar to the former in nature. In this stage 

 the chromatin of the cells was distributed more or less irregularly in 

 the cytoplasm; in some it was diffused throughout, while in others, dis- 

 tinct chromatin granules were demonstrable. A further advanced stage 

 of the jDarasites which occurred in cultures was a vacuolated, globular 

 form which retained its staining property just as nonvacuolated cells do. 

 (PL II, fig. 5.) As a result of the distension of the vacuole, the parasite 

 gradually assumed the shape of a large ring, of which the thickest part 

 contained some chromatic dust. (PL II, fig. 6.) In addition to these, 

 there were many degenerated cells of an allied nature, which were prin- 

 cipally characterized by the numerous vacuoles and hypertrophic chroma- 

 tin. (PL II, fig. 7.) The change which took place within the next 

 twenty-four hours was very interesting. The ring-shaped cells (PL II. 

 fig. 8) in which the chromatic dust had already become rearranged so as 

 to form a large nucleus and a small blepharoblast, .transformed themselves 

 into spindle-shaped organisms in which no visible flagella were present. 

 Associated with this form was observed the flagellated motile parasite 

 (PL III, fig. 9) which morphologically was almost identical with the 

 former. 



Finally, in the 72-hour culture we obtained a flagellated form showing . 

 the development of an undulating membrane. The size of this form, 

 which was that of a typical trypanosoma, increased and afterwards it 

 multiplied in the manner usual for true trypanosomata — that is, by long- 

 itudinal fission (PL III, figs. 10 and 11) — thereafter, as has already 

 been mentioned, the fullgrown and divisional forms increased in number. 11 



The recent observation of E. Koch 12 in regard to the developmental 

 changes of piroplasma are of great interest, for he described several forms 

 encountered in the body of ticks which in some respects resemble those 

 obtained by us in culture. In the first place, his most predominating 



11 A detailed account of these developmental forms of Piroplasma parvum 

 must be left for our more complete paper on the subject. 

 12 Deutsche Med. Wchnsch. (1905), 47, 1865. 



