108 Mr. Gulliver's Contributions to 



vol. xvi.) p. 106-107, I have noticed that the blood-discs of 

 mammalia become smaller after the removal of their colouring 

 matter by repeated additions of water. Thus some human 

 corpuscles having an average diameter of j^gth of an inch, 

 measured only yg^frth after the whole of their colouring mat- 

 ter had been separated in this manner, when they appeared 

 flat and pellucid, very faint, and obviously differing in size and 

 general characters from the particles usually described as the 

 nuclei of the blood-corpuscles. No nuclei can be discerned in 

 these washed corpuscles, either by the aid of acids, of cor- 

 rosive sublimate, or of iodine. 



The first part of the preceding observation agrees in some 

 essential points with the results obtained by Sir E. Home 

 (Phil. Trans., 1818, pi. viii. figs. 1, 2, and 3), Schultz (Lan- 

 cet, 1838-39, vol. ii. p. 713), and Donne (Mandl, Anat. Mi- 

 cros., liv. i. p. 8-9). 



If the colouring matter be in like manner washed com- 

 pletely from the blood-corpuscles of the lower vertebrata, both 

 the nuclei and envelopes will remain, the latter becoming 

 quickly circular, and the former also after a few hours. Sub- 

 sequently the envelopes are scarcely visible, and the colourless 

 matter of the corpuscles, which subsides in the water, appears 

 to be composed chiefly of the nuclei, although with the aid of 

 iodine many of the envelopes may be seen; and these are more 

 or less reduced in size after a few days, especially in warm 

 weather. Corrosive sublimate affects them very feebly, although 

 it instantly increases the opacity of the washed corpuscles of 

 mammalia. When the former corpuscles have been kept some 

 days in water, the envelopes become very irregular, and hardly 

 perceptible by any means ; the size of the nuclei is diminished, 

 and they at length break up into extremely minute molecules. 



Dilute muriatic acid renders the nucleus clearly visible in 

 the blood-corpuscles of the oviparous vertebrata. If the cor- 

 puscles of a mammal be treated with the same acid, many of 

 them appear shrunk and puckered, notched at the edges, and 

 granulated ; some present a distinct central spot, irregular at 

 the margin, like a granular nucleus ; others remain smooth 

 at the circumference, often misshapen, and generally with a 

 dark or brilliant central part, according to the focal distance 

 in which they are placed. 



The two following figures will illustrate the foregoing ob- 

 servations. The blood-corpuscles of man, and of an adult 

 bird, with some fibrine from the blood of the latter, are re- 

 presented as magnified about 820 diameters. 



Fig. 1. Outlines of blood-corpuscles of Man. In the lower 

 part of the figure, at A, corpuscles in pure blood from a prick 

 of the finger : some of them, lying flat, exhibit the central 



