TISSUES OF THE BODY. 231 



tion of the cornea, remained undiscovered : the latter also in the foetus, 

 it appears, yields no chondrin. 



The ground substance of connective-tissue remains unchanged in cold 

 water, alcohol, and ether, and swells up into a jelly-like mass under the 

 action of acetic acid, which only dissolves it to a certain extent when 

 warm, and after a considerable lapse of time. Potash, on the other hand, 

 commences to dissolve it even when cold. By boiling in water this inter- 

 cellular matter is converted into glutin ( 15), but whether in toto is still 

 an unsettled question. The time necessary for this is liable to variation, 

 according to the quality of the connective-tissue on which we are work- 

 ing. As to the process also by which the collagenic tissue is trans- 

 formed into glutin, we are as much in the dark here as elsewhere. And 

 if in the analysis of portions of connective-tissue the same results per 

 cent, have been obtained as in the case of the glue prepared from the 

 latter by boiling, it only speaks for the imperfection of the chemical 

 manipulation. It is, in fact, impossible to elucidate with any degree of 

 accuracy the constitution of this intercellular matter, in that we possess 

 no means of separating it from the numerous form elements entangled in 

 its substance, namely, connective-tissue corpuscles, elastic fibres, &c., 

 without even taking into account other accidental and unessential tissue 

 elements, such as blood-vessels, fat cells, &c. The substance cementing 

 the fibrillae together is soluble in permanganate of potash (Rollttt), 

 10 per cent, solutions of common salt and in baryta and lime water; these 

 take up from tendinous tissue an albuminous substance giving the reactions 

 of mucin (Rollett). 



The composition also of connective-tissue corpuscles is but to a small 

 extent known, on account of our being obliged to base almost all our con- 

 clusions on microchemical reactions. Their nuclei show the usual resist- 

 ance to acetic acid, and the protoplasm it appears in the tendon-cells of 

 the mature body to be reduced to a minimum though it may become 

 greatly changed by the action of water alone, still offers to that of acids 

 considerable opposition. Jt holds out against concentrated mineral acids 

 for a period in which the connective intermediate substance is softened 

 into a pulp or dissolved (2). Hot solutions of potash, on the contrary, dis- 

 solve the whole cell rapidly, and are thus of importance in the demonstra- 

 tion and diagnosis of elastic elements. The latter only admit of nearer 

 investigation in those parts in which they are met with in great prepon- 

 derance, as in the ligamentum nuchse, and to this is due the slight 

 acquaintance we possess with elastic matter in general ( 15). 



Those homogeneous elastic membranes of large vessels already discussed 

 ( 127), as well as the structureless intermediate substance of many elastic 

 fibrous networks, resemble in their microchemical bearing ordinary elastic 

 fibrous tissue. The homogeneous envelopes of certain of the connective- 

 tissue bundles appear still to consist of glutinous substance, in that they 

 give way to the action of caustic alkaline solutions, while in other 

 instances they are decidedly composed of elastic material (comp. 128). 

 The transparent limiting layers of connective-tissue membranes likewise 

 are liable to the same variation in composition. Descemefs membrane ori 

 the cornea is elastic, while the anterior transparent lamina of the latter 

 and the basement membranes are of glutinous nature. 



These facts just stated are, however, of interest in another way. They 

 show that elastic matter represents a product of the subsequent transfor- 

 mation of glutin-yielding intermediate substance, and, moreover, of that 



16 

 



