PROTOZOA INCERTM SEDIS 



535 



Protozoa Incertse Sedis. 



Cytoryctes variolse Guarnieri, 1892. 

 Synonym. — Strombodes jeuneri Sjobrung, 1902. 



In 1892 Guarnieri described peculiar parasitic bodies in lesions of smallpox, 

 and in those produced by vaccination of the cornea of rabbits, etc. Pfeifier, 

 in 1893, confirmed these findings, as did Jackson Clarke in 1894, and 

 Wasielewski in 1897. Councilman, Magrath, and Calkins, in 1903, published 

 the full account of the life-history of the parasite, and their findings have 

 been confirmed — in part, at least — by De Korte in 1905. 



In its youngest form Cytoryctes vaviolcs is seen in the cells of the skin as a 

 minute spherical homogeneous body, 0*7 jjl in size. No differentiation into 

 nucleus and cytoplasm is possible, as the organism appears to be all nucleus. 

 The parasite grows to 3 fju, and then shows a vacuolization in the centre, 

 with sometimes a central dot. The periphery next shows minute unstained 

 dots, which, when they become larger, take on the green of a Borrel's stain. 

 The red staining material is called by Calkins protogonoplasm. 



The organism can now change its shape and throw out pseudopodia, and 

 lives in a vacuole near the nucleus; there is no ectoplasm or endoplasm, no 

 vacuoles, but only chromatin granules of protogonoplasm. Volpino has 

 described minute motile granules in the epithelial cells, which he considers 

 to be the true parasites. 



Auto-Infection. — In a large parasite (10 to 14 fju) the protogonoplasm is dis- 

 tributed through the body in minute spherical granules lying in a minute 

 vesicle, forming granules from 0-7 to i in diameter, which are liberated by 

 disintegration of the framework of the host cell, while the rest of the cyto- 

 plasm form a nucleus de reliquat. 



Sexual Development, — The homogeneous granules or gemmules may start 

 the cycle of cytoplasmic organisms again, or may become germ-cells in the 

 nucleus. The gemmules reach the nucleus, but they now stain uniformly 

 and become minute, clearly-defined, homogeneous bodies — female gameto- 

 cytes. Sometimes they fail to reach the nucleus and remain in the cytoplasm, 

 in which they can only partially develop. Within the nucleus Calkins thinks 

 they form male and female gametocytes, homogeneous granules, or the 

 gemmules become spherical, with central red masses, and later red masses 

 at the periphery — the male gametes. No conjugation has been observed. 



The zygote is an amoeboid body lying in the nucleus, and staining deeply, 

 This zygote becomes a pansporoblast and the mother-cell of the sporoblasts. 

 The spore is very minute, and contains a vacuole ; it migrates, and may travel 

 into the nucleus and form secondary sporoblasts. 



Cytoryctes (Doubtful Species). 



This organism can be found as corroid bodies in the smears taken from the 

 heart muscle of animals suffering from foot and mouth disease. 



Neuroryctes hydrophobise Calkins, 1907. 



Neuroryctes hydrophobics, better known as the Negri bodies, because they 

 were discovered by Negri in 1903 as round or oval bodies, i to 23 ^ in length, 

 in the nerve-cell of the brain, especially the Cornu ammonis, of animals 

 suffering from hydrophobia, are now generally accepted as the cause of the 

 disease. Hydrophobia is so common in India and Ceylon that a knowledge 

 of its parasite is necessary to the practitioner in that part of the tropics. 



Some authorities consider these bodies to be cell-structures, but in our 

 opinion there cannot be any doubt that they are parasites, especially after 

 the further investigation of Negri, amply confirmed by Williams, Lowden, 

 and Calkins, who named it Neuroryctes hydrophobic Calkins, 1907- Prowazek 

 believes them to be Chlamydozoa. When stained by Giemsa the protoplasm 

 takes on a bluish tinge like the malarial organism, while there is a central 



