SECT. 26.] CONNECTIVE TISSUE. 59 



plexus, choroid coat), with which, as in the choroid, other peculiar 

 elements may be associated, viz., anastomosing cells, filled more or 

 less with pigment, which are probably to be ranked with the plasm- 

 cells of connective tissue. 



i. The homogeneous membranes of connective tissue. In many 

 organs, membranes are met with which agree in aspect, and partly 

 in chemical nature, with connective tissue, but do not possess dis- 

 tinct bundles and fibrillar, and rather appear homogeneous. Under 

 this head I reckon, the homogeneous tissues which often envelop the 

 bundles of the arachnoid separately or several together, the neuri- 

 lemma of small nervous trunks, the hyaloid membrane, the envelopes 

 of the Malpighian corpuscles of the spleen, and of the glandular fol- 

 licles of the alimentary canal (tonsils, follicles of the tongue, solitary 

 and Peyer's glands). Of the envelopes of glandular elements, 

 all those which contain nuclei (or plasm -cells) belong to this di- 

 vision, as those of the testicles, Graafian follicles, and of certain 

 racemose and tubular glands ; on the other hand, I cannot class 

 with connective tissues the homogeneous, non-nucleated, true 

 membrance propria , such as those occurring along with the former 

 in the seminal tubules and Graafian follicles, and especially those 

 of the uriniferous tubules, on which point I would refer to § 16. 

 In like manner, the capside of the lens, the Membrana Demoursii, 

 Membrana limitans, and the sheath of the chorda dorsalis, also 

 appear to me to owe their origin to the excretion of matter from 

 cells, and not to belong to this division; while, as regards the 

 structureless membranes occurring under epithelial and epidermic 

 layers, or the basement membranes, I refrain, for the present, from 

 giving an opinion. There is much in favour of the view, that they 

 are only the outermost layer of the membrane (of connective 

 tissue) which they limit, while it is also possible that they may 

 belong genetically to the cells which they support. 



k. Loose or areolar connective tissue (amorphous connective 

 tissue, Henle). This consists of a lax network of anastomosing or 

 variously interwoven bundles of connective tissue, which occur in 

 greater or less quantities between the organs and their individual 

 parts. It appears in two forms: i. As adipose tissue, Avhen nume- 

 rous fat-cells are contained in the meshes of a connective tissue 

 poor in elastic fibres and plasm-cells. 2. As ordinary loose con- 

 nective tissue, when the fut-cells are scanty or altogether absent. 



I. Adipose tissue chiefly occurs in the integument as panniculus 

 ndiposus; in the large cylindrical bones, as yellow bone-marrow; 



