392 Dr. W. Osier on Organisms [June 18., 



In size they vary greatly, from half or quarter that of a white blood- 

 corpuscle, to enormous masses occupying a large area of the field or 

 even stretching completely across it. They usually assume a somewhat 

 round or oval form, but may be elongated and narrow, or, from the 

 existence of numerous projections, offer a very irregular outline. They 

 have a compact solid look, and by focusing are seen to possess consider- 

 able depth ; while in specimens examined without any reagents the fila- 

 ments of fibrin adhere to them, and, entangled in their interior, white 

 corpuscles are not unfrequently met with. 



It is not from every mass that a judgment can be formed of their true 

 nature, as the larger, more closely arranged ones have rather the appear- 

 ance of a granular body, and it is with difficulty that the individual 

 elements can be focused. When, however, the more loosely composed 

 ones are chosen, their intimate composition can be studied to advantage, 

 especially at the borders, where only a single layer of corpuscles may 

 exist; and when examined with a high power (9 or 10 Hartnack) these 

 corpuscles are seen to be pale round disks, devoid of granules and with 

 well-defined contours. Some of the corpuscles generally float free in the 

 fluid about the mass ; and if they turn half over their profile view has the 

 appearance of a sharp dark line (%. 5, a & b). In water the individual 

 corpuscles composing the mass swell greatly ; dilute acetic acid renders 

 them more distinct, while dilute potash solutions quickly dissolve them. 

 Measurements give, for the large proportion of the corpuscles, a diameter 

 ranging from one 8000th to one 10,000th of an inch ; the largest are as 

 much as one 5000th, and the smallest from one 15,000th to one 24,000th 

 of an inch ; so that they may be said to be from -l-| the size of a red 

 corpuscle. In the blood of cats, rabbits, dogs, guineapigs, and rats the 

 masses are to be found in variable numbers. New-born rats are specially 

 to be recommended as objects of study, as in their blood the masses are 

 commonly both numerous and large. They occur also in the blood of 

 foetal kittens. 



Considering their prevalence in disease and among some of the lower 

 animals, they have attracted but little notice, and possess a comparatively 

 scanty literature. The late Prof. Max Schultze * was the first, as far as 

 I can ascertain, to describe and figure the masses in question. He speaks 

 of them as constant constituents of the blood of healthy individuals, but 

 concludes that we know nothing of their origin or destiny, suggesting, 

 however, at the same time that they may arise from the degeneration 

 of granular white corpuscles. Schultze's observations were confined to 

 the blood of healthy persons, and he seemed of the opinion that no 

 pathological significance was to be attributed to them. 



By far the most systematic account is given by Dr. Biess t, in an 



* Archiv f. mik. Anat. Bd. i. 



t Keichert u. Du Bois-Keymond's Archiv, 1872. 



