TISSUES, ORGANS, AND SYSTEMS. 87 



in some places, they appear to retain more their original character of 

 a system of canals ; yet I can by no means allow, that these nucleus- 

 fibres are to be regarded as a system of tubules subserving nutrition. 

 In my opinion, all fine elastic fibres, which no longer present any trace of 

 the original cell, i. e. those of the areolar connective tissue of i\iQ corium, 

 fascise, of the perimysium, of the periosteum, of the dura mater, of the 

 serous membranes, of the walls of the vessels, and of mucous membranes, 

 are solid fibres, and only of service to the organism so far as they are 

 elastic. 



A relation to nutrition can only be supposed of those elastic elements 

 of the tendons, ligaments, and of the cornea, which present condi- 

 tions more nearly embryonic ; but even with respect to these it does not 

 appear so evident that it can be decidedly afiirmed. In the tendons 

 and ligaments, for instance, it is plain that a part only of the elastic 

 elements are not quite fully developed, so that possibly cavities may still 

 exist in them ; while the rest, much more considerable, are as com- 

 pletely developed as elsewhere, and offer no trace of a cavity. If, 

 now, it were assumed that the former have a determinate relation to 

 the conduction of the nutritive fluid, it would yet remain unexplained 

 w'hy, in certain regions, these organs were more favored than in others. 

 If it be further considered, that in the tendons and ligaments, as in the 

 connective tissue in general, vegetative molecular changes and nutri- 

 tion are assuredly at their lowest stage, — furthermore, that the arrange- 

 ment of the nucleus-fibres (their more longitudinal course, the want of 

 anastomosis of the nucleus-fibres of the different secondary bundles in 

 tendons) appears very little fitted to conduct nutritious fluids from the 

 surfaces of these organs, where only the vessels are found, into their 

 interior, — ^there will appear no great necessity for entering further into 

 this hypothesis. For the cornea alone, where the elastic tissue remains 

 in a quite embryonic stage, should I be inclined to adopt Virchow's 

 hypothesis ; and, as respects the other tissues, I can only grant that, 

 when the elastic elements are in such an imperfectly developed condi- 

 tion that they still contain canals for greater or less distances, they 

 may have a share in the distribution of the nutritive fluid which natu- 

 rally interpenetrates these organs, and, therefore, in their nutrition, but 

 that this must rather be regarded as a secondary function, and will not 

 justify their approximation to the fine canals of the teeth and bones, 

 which exist specially for the purpose of nutrition. 



Such a function might much rather be ascribed to the undeveloped 

 nucleus-fibres and their formative cells in the immature (pathological 

 or normal) connective tissue ; for here, at least, the anatomical and 

 physiological relations of the tissue are not opposed to such an assump- 

 tion; it would amount to little more, however, than what may be asserted 

 of every undeveloped fibrous tissue. 



