Action of certain Reagents upon Coloured Blood- Corpuscles. 127 



around the nuclei. The processes attaching the masses of coloured 

 matter to the nucleus often appeared to be membranous in character. 

 Many of the corpuscles ultimately became perfectly spherical, the 

 nucleus being indistinctly seen in the centre or at one side. These 

 spherical corpuscles were often seen to contain several globular masses 

 grouped usually around the nucleus. Very often the ultimate effect 

 was to leave the nucleus with a dark yellow rounded knob of the 

 coloured part of the corpuscle at either end of it. Sometimes the 

 whole of the coloured part of the corpuscle had disappeared, leaving 

 the nucleus pale and swollen, and with indications of a plexus in its 

 interior. (These peculiar forms which the corpuscles assume may be 

 preserved some time by sealing up the preparation.) 



From some of the corpuscles long delicate processes were observed 

 to pass. Some of these processes appeared to be made up of 

 minute globules of coloured material which had coalesced to form 

 a continuous bead-like string. They resembled very much the 

 processes seen passing from the blood-corpuscles of the frog after 

 treatment with a 20 per cent, solution of urea. Other processes 

 appeared to be of a membranous character, and were tipped at their 

 free extremities by a minute coloured globule. 



All these processes were remarkable for their length, which was 

 sometimes several times that of the corpuscle itself. They were more 

 easily induced in the corpuscles by gently heating the slide over a 

 spirit-lamp. 



If some of the blood of a newt be kept for forty-eight hours in a 

 5 per cent, solution of ammonium chromate, it will be found on 

 examining it that in most of the corpuscles the perinuclear part has 

 entirely disappeared, leaving the nucleus much swollen and of a 

 globular form. An intranuclear plexus with wide meshes is seen. 

 The nucleus stains readily — though not very deeply — with picro- 

 carmine, the interior of the nucleus becoming reddish in colour and 

 the envelope yellowish. (Various forms assumed by the corpuscles are 

 shown in Fig. 7.) 



The action of this substance on the coloured blood-corpuscles of the 

 frog is accurately described by Mr. Dowdeswell as far as regards the 

 extension, retraction, and detaching of the protuberances, and he 

 remarks that no rupture of a membrane, or anything of the kind, was 

 to be seen, even with a power of 1,000 diameters. Dr. Klein* has 

 also shown the immense importance of this substance for a variety 

 of purposes, but especially for revealing the fibrillar plexuses within 

 cells and nuclei, e.g., in non-striped muscle, &c. 



Urea. 



A 20 per cent, solution of urea first caused the corpuscles to become 

 * " Quart. Journ. Mic. Sc.," 1878, 1879. 



