156 G. F, DOWDESWELL. 
A solution of picric acid shows the structure of the nucleus 
well, and with this permanent preparations may be made. As 
far as | am aware, the intimate structure of the nucleus of 
the red blood-corpuscle has not been described, excepting by 
Dr. Schmidt, in the blood of Amphiuma! and some other ani- 
mals. He describes and figures the nucleus as granular, and 
invests the corpuscle itself with a membrane, which, whatever 
it may be in the case of Amphiuma, appears certainly not 
to be so in other animals; its existence seems to be clearly 
incompatible with the production of the above-described pro- 
cesses, as much as with the well-known experiment of Dr. 
Beale, of breaking up by pressure with the point of a needle, 
on the covering-glass, a red corpuscle into several small drop- 
lets. In frog’s blood, too, its absence seems clearly de- 
monstrated by treating it in the cold with a 5 per cent. solu- 
tion of ammon. chromate, when the corpuscles are at first little 
altered in appearance, excepting that the nucleus becomes pale 
and distinct. After some minutes protuberances appear on 
different parts of the periphery of the corpuscle ; some of these 
are then extended, and form long processes, two or three 
times the diameter of the corpuscle, of very appreciable thick- 
ness, and distinctly coloured ; the size of some of these amounts 
to a material portion of the corpuscle, the membrane of which, 
if if existed, must be ruptured by their protrusion, and would 
be clearly apparent under an amplification of 1000 diameters or 
upwards, but nothing of the kind can be seen. The processes 
formed in this case are frequently retracted again completely, 
even the largest of them, and the appearances are most in- 
teresting and instructive ; after a very short time the processes . 
disappear, are retracted or detached ; the corpuscles then become 
circular and colourless. Under the influence of this reagent the 
corpuscles seem to become more plastic than normally, in the 
same manner as when subjected to heat. 
As above-mentioned, I found that these appearances were first 
recorded by Dr. William Addison, in 1861 (loc. cit.). He de- 
scribes the action of acids and alkalis, of various salts, and other 
reagents upon the blood. He obtained the processes in question 
most readily by treating the blood upon the slide with sherry 
wine, either by itself or with the addition of different salts, and 
found that neither quinine, morphia, nor strychnine, added to the 
preparation, nor even the vegetable alkaloids in large propor- 
tions, prevented their appearance, but that a very small pro- 
portion of bichloride of mercury did so effectually. Dr. Addison 
gives a plate with the different forms of the processes admirably 
figured, and his paper forms a very complete account of them. 
1 ¢ Journ. R. Mic, Soc.,’ vol. i, 1878, pp. 57 and 97. 
