458 



SPECIAL HISTOLOGY. 



base of the brain to the termination of the canal of the dura 

 mater medulla, the fluid in question may be readily obtained. 

 It is alkaline, contains — of water 98' 56 — albumen and ex- 

 tractive matter 055 — salts 084 per cent., principally chloride of 

 sodium. Its principal function appears to be to conduce to the 

 more free motion of the central nervous system, and to act as a 

 regulator in the varying degrees of fulness of the vascular 

 system. 



LA few pathological points may here be referred to. The 

 ependyma ventriculorum presents not only, as above mentioned, 

 almost constantly in places, a thin fibrous substratum, but is 

 frequently, especially in dropsy of the ventricles, and in old 

 age, very much thickened by a layer of that kind. In either 

 case it invariably contains, as was first mentioned by Purkinje, 

 yellowish bodies, with concentric stripe of a round or biscuit 

 shape, and not unlike starch grauules. They are scarcely 

 affected by acids, whilst in caustic alkali they become pale 



Fig. 153. 



and gradually dissolve. I find these cor- 

 puscula amylacea (fig. 153), almost always 

 on the fornix, the stria cornea, and septum 

 pellucidum, and also elsewhere in the walls 

 of the ventricles, as well as in the cortical 

 substance of the brain, in the medullary sub- 

 stance of the cord, and in the filum terminate; 

 in the first-mentioned situations they fre- 

 quently occur in incredible quantity, close 

 together, in the newly formed connective 

 tissue, or between the nervous elements. 

 That these bodies are a pathological pro- 

 duct is certain, but not so of what they 

 _ consist, or how thev are formed, although 



everything indicates a nitrogenous sub- 

 stance, and a formation from successive deposits. In the 

 plexus chorioidei, in the pineal gland, occasionally in the 

 pia mater and arachnoid (also in the cord), and, although 

 rarely, also in the walls of the ventricles, there is further- 

 more met with, as a constant, though pathological production, 



Fig. 153. 1, " Brain-sand" from the pineal gland, in bundles of connective tissue; 

 2, corpuscula amylacea from the ependy)iia of Man ; x 350 diam. 



