Scientific Proceedings. 



(89) 25 



by the peripheral ring of the nucleus of the host cell. This cap 

 may extend, and usually does, around two-thirds of the cell, and 

 even more. The blepharoplast is easily seen in female cells ; 

 microgamete formation common. No infection of other birds by 

 injection of blood swarming with these forms. 



Hcemoprotens ziemanni, Lav., has been studied by Danilewsky, 

 Ziemann, Laveran, Schaudinn, and others. Forms long spindle- 

 shaped bodies, which are 30 to 50 microns in length. The authors 

 have found this species, or one closely related to it, in the blood 

 of a hawk. Sexual forms easily recognized. 



Hcemoproteus rouxii, n. sp., is very common in sparrows, and 

 represents the very earliest possible infection of young erythro- 

 blasts, so much so that it is not feasible to exclude the possibility 

 of their being leucocytes. As the parasite grows it pushes into 

 the nucleus, which assumes the form of a thick crescent. The 

 parasite measures from 4 to 6 microns. Its plasma does not stain 

 readily, and sexual forms have not as yet been recognized. Ap- 

 parently always associated with this cytozoon are minute cres- 

 centic free hemogregarines. These are but 4 microns long, and 

 are motile, crawling over the red blood cells in characteristic man- 

 ner. Larger motile crescents, about 10 microns long, at times are 

 present. Both large and small crescents are free and motile, and, 

 it is important to note, are present in the fresh blood at the moment 

 when drawn. They cannot, therefore, be considered as ookinetes. 

 They are hemogregarines, and presumably constitute the extra- 

 cellular stage of H. rouxii. 



It is to be noted that the last four mentioned forms all exert 

 pressure on the nucleus of the erythroblasts, and, as a result, give 

 rise to very peculiar types. They are all " leucocytozoa " of which, 

 thus far, there has been but one recognized type, that of H. zie- 

 manni. The view of Schaudinn that the latter is a trypanosome 

 which ingests an entire erythroblast by attaching itself to such by 

 one end becomes untenable, inasmuch as all stages of infection 

 from the earliest to the latest can be readily observed in the case 

 of H. sacharovi and H. majoris. The authors regard the large 

 spindle-shaped H. ziemanni as an infection of an erythroblast, and 

 the elongated form as consequent upon an alteration of the wall of 

 the host cell leading to increased osmotic pressure, which, acting 

 on the poles, gives rise to the spindle-shaped forms. 



