80 



MANUAL OF HISTOLOGY. 



diately under them thin laminae are formed, probably from 

 the effused fibrine the commencement of fibrillation. 



As the corpuscles become smaller their envelope shrinks, 

 and they recede from one another. Yet, in many cases, they 

 may retain connection with one another by means of their pro- 



cesses. In advanced life these cor- 

 puscles are generally more or less 

 flattened, but their form is also con- 

 siderably modified by the age of the 

 tissues and various mechanical alter- 

 ations to which they are subjected, 

 according to the particular locality 

 in which they occur or the province 

 they have to fill. 



By referring to Fig. 32 it will be 

 seen that the delicate protoplasm, Z>, 

 has processes which corne clearly in- 

 to view where the corpuscles are iso- 

 lated. 



Pavement endotJielium (epitheli- 

 um). From the views that have been 

 advanced it is plain that we are pre- 

 pared to abandon the old idea that the 

 mesentery, peritoneum, the pleura, 

 endocardium, serous cavities, and ten- 

 Fl( ^ 32 Development of fibrous tis- dinous sheaths are lined with epithe- 



sue. Fibroma of the scalp. r 



lium. It is becoming more and more 



evident from studies in the lymphatics that they are lined with 

 connective-tissue corpuscles, which, on the one hand, are in 

 actual continuity with the interfascicular connective-tissue cor- 

 puscles, and, on the other, with the pavement corpuscles of 

 the serous cavities. It is but a step farther and in the same 

 direction to trace the endothelium of the endocardium out 

 through the arteries and veins into the capillaries and recog- 

 nize the connective-tissue corpuscle as the one cellular element 

 of all these tissues. The special methods by which these parts 

 are studied may be found described in the chapters more es- 

 pecially devoted to these topics. Nitrate of silver and chloride 

 of gold are still prominent among the reagents that demon- 

 strate them most distinctly. 



Ehrlich has recently described peculiar connective-tissue 



