148 CHEMICAL COMPOSITION OF NUCLEI OF BLOOD CORPUSCLES. 



rather zooids of the blood corpuscles are obtained as a ^vhite 

 powder, which sinks very slowly in water ; in the latter, as a 

 mass resembling fibrin in appearance. Microscopic examina- 

 tion shows this powder to consist of the nuclei in the form of 

 small round bodies containing several dark granules, surrounded 

 by a ring of transparent colourless substance, apparently a 

 remnant of stroma, whose breadth is about equal to the diameter 

 of the nucleus, and whose edge is so delicate as to be scarcely 

 perceptible. On the addition of aniline red or blue, dissolved 

 in dilute alcohol, the nucleus becomes deeply coloured, the 

 stroma slightly so, and its edges much more distinct. Weakly 

 alkaline solutions of carmine and solutions of iodine also colour 

 the nucleus deeply, but the stroma very slightly, or not at all. 

 The nucleus is generally in the middle, but, occasionally, is more 

 or less eccentric, and sometimes sticks quite close to one side of 

 the surrounding substance. This last may possibly be its con- 

 stant situation, and its central one only apparent, and it may 

 thus correspond to the point in mammalian blood corpuscles, 

 which was found by Eoberts* and Eindfleischf to become 

 deeply coloured by magenta. If the powder be then shaken 

 with ether and ^vater it forms a layer between the two; and 

 when this is microscopically examined, the nuclei alone are seen, 

 the stroma formerly surrounding them being no longer percep- 

 tible even after the addition of aniline. The nuclei may be got 

 at once by treating the corpuscles with ether, separating the 

 nuclear layer by a stoppered funnel, and then washing in water. 

 Alkalis cause the nuclei to swell, to run together in clumps, 

 become indistinct, and finally disappear. Dilute mineral acids 

 or acetic acid cause them to shrink and become more sharply 

 defined. A small, strongly refracting point, resembling a 

 nucleolus, and seeming to take up the colouring matter more 

 strongly than the rest, also becomes visible ; but this appear- 

 ance may be due to a change of shape in the nucleus, occasioned 

 by the acid. Concentrated mineral acids cause them to shrink 

 much, to run together, become indistinct and disappear. The 

 stroma surrounding the nuclei swells and shrinks somewhat^ 



* Proceedings of Royal Society, 18fi3. 



f Experimental Studien iiber die Histologie des Blutes. 



