I902 



DISEASES OF THE CIRCULATORY SYSTEM 



scribed, as well as of such pseudo-parasites as those mentioned by 

 Balfour as being described by Foran and Breeze. The dark ppot 

 mentioned as being visible in the maraglianos may be the centro- 

 some, 



A granule from a leucocyte or a blood platelet lying on an erythro- 

 cyte may simulate a parasite. 



Leucocyte. — The leucocyte, especially the eosinophile, is 

 responsible for the free granules, and worse for the free or attached 

 wavy process, which is apt tobe mistakenfor a spirochaete, especially 

 when a beginner is using the dark-ground illumination. 



Stained Blood — Erythrocyte. — When the glassy body swells it 

 gives rise-to pale large red blood cells 15-50 microns in diameter, 

 which are the half-moon-shaped or sickle-shaped corpuscles of 

 Stephens and Christophers. 



The hsemoiyzed stroma is the cause of the shadow corpuscles, and 

 polychromatophilia is due to diffuse colouring of the reticulum, 

 while the punctate form is due to the nodes being especially tinted. 



Schuffner's dots are caused by the coloration of nodes of the reti- 

 culum in older cells, while pathological karyolysis of the nuclear 

 plate may be the cause of the Howell-Jolly bodies and the ring- 

 shaped bodies of Cabot, and perhaps the so-called Paraplasma 

 flavigemtm is due to the same cause. 



The capsule corpuscle may be the origin of Arnold's nucleoids, 

 Schmauch's bodies, Heinz's corpuscles, and many pseudo-parasites. 



A blood platelet lying on an erythrocyte may resemble a malarial 

 parasite. 



Leucocyte. — The puzzles in connection with the leucocyte or 

 lymphocyte may be divided into: — 



r. Extranuclear. 

 2. Intranuclear. 



Extranuclear. — Kurloff's bodies seen in the large lymphocytes, 

 especially in guinea-pigs, are large vacuoles with a homogeneous 

 structure, and may be a secretion, but have been considered to be 

 parasites. They take a purplish or reddish colour with Giemsa's 

 stain. 



Oval or round rings may possibly be connected in some way with 

 the area around the centrosome. Ferrata's plasmosomes are small 

 metachromatic bodies which are thought to indicate retrogressive 

 changes; they may be derived from the chromatin of the nucleus. 



In 19 12 Castellani described extranuclear non-parasitic bodies in 

 leucocytes. They take, with Giemsa's stain, a blue colour, almiost 

 constantly show dots of chromatin, and measure 2-6 microns in diam- 

 eter. They also occur free in the liquor sanguinis, and are by him 

 considered to be degenerate red blood cells engulfed by the leucocyl e. 



Intranuclear. — The nucleus of the mononuclear leucocyte is apt 

 to undergo changes and to show bodies with a blue cytoplasm, with 

 or without chromatinic spots, which look very like parasites, as also 

 described by Castellani in 1913, 



