126 ORGANISED FLUIDS. 



mucus mixed up with true mucous corpuscles, belongs not to 

 the fluids, and will be given in detail under the head of 

 Epithelium, in that division of the work which is devoted to 

 the consideration of the solids of the human body; the 

 structure, form, size, properties and nature of the true 

 mucous corpuscles may here t^ described with advantage. 



MUCOUS COEPUSCLES. 



Structure. The mucous corpuscles, which are colourless 

 and mostly of a circular form, are each constituted of a 

 nucleus, an envelope, an intervening fluid substance, and 

 numerous granules, which are diffused generally throughout 

 the entire of the corpuscles, being contained within the cavity 

 of the nucleus, in the space between this and the outer enve- 

 lope, and, lastly, in the substance of the envelope itself; this 

 arrangement imparting a granular texture to the entire cor- 

 puscle. (See Plate XL) 



The nucleus, like the corpuscle itself, is a circular body of 

 about one-third, or one-fourth its size: it sometimes occu- 

 pies a central, but very frequently an eccentric position in 

 the mucous globule : it is not at all times visible, although 

 very generally so, without the addition of re-agents, the best 

 being water and acetic acid. 



The addition of water to mucous corpuscles discloses, in 



the majority of them, but a single nucleus (see Plate XI. 



fig. 3.) ; in some, however, two and even three or four nucleoli 



appear, these resulting from the division of the substance of 



the single primary nucleus. 



The effect of a weak solution of acetic acid is the same as 

 that of water, except that an additional number of corpuscles 

 are seen after its application to possess the divided nucleus, 

 whilst in others the single nucleus is observed to be oval, 

 and occasionally contracted in the centre, this form being 

 the transition one from the single to the double nucleus. 

 (See Plate XI. fig. 4.) 



If undiluted acetic acid be used, then all the corpuscles 

 will present a compound nucleus, consisting of two, three, 



