188 



MANUAL OF HISTOLOGY. 



fat. This may be designated for the present as sustentacular nervous 

 matter, and is a species which has, up to the present, been investigated 

 least of all. 



The fibrous character of most of the tissues enumerated here is by no 



Fig. 178. Reticular connective-substance with lymph corpuscles from 

 Peyer's follicle of the adult rabbit, a, capillaries ; 6, reticular frame- 

 work; c, lymph cells (most of the latter have been removed by 

 brushing). 



means lost, however; for we frequently see, whether in the course of 

 physiological development or as a pathological occurrence, many of these 

 tissues, the mucoid as well as the reticular, becoming 

 transformed into ordinary fibrous tissue, in that the 

 cellular network obtains coatings of filaments while 

 the gelatinous intercellular matters, or as the case 

 may be, lymphoid corpuscles, decrease and finally dis- 

 appear. 



Then, again, we recognise that other substitu- 

 tion already mentioned section 101, in different 

 groups of animals. Thus, for instance, the reti- 

 cular connective-substance in one organ of certain 

 animals is replaced by ordinary fibrillated connective-tissue in other 

 species, and so on. Finally, it seems probable that any of the other 

 tissues belonging to this so wide)y distributed connective-substance group 

 are all capable more or less of reproducing from their cellular offspring 

 either mucoid or reticular tissue. 



Fig. 179. Sustentacular 

 tissue from the poste- 

 rior column .of the 

 human spinal cord. 



o 



We have just seen that by gelatinous or mucoid tissue is understood a 

 cellular structure, characterised by possessing a very soft and watery 

 intercellular substance, containing either mucin or some matter very 



