43 



FOURTH LECTURE. 



puscles of the spleen also belong here. The tissue of the 

 spleen pulp is still more strongly modified. 



The mucous membrane of the small intestine also contains 

 our tissue ; although the number of lymphoid cells is here much 

 less, and the cell processes not unfrequently appear broader, 

 lamelliform. In the large intestine, finally, something inter- 

 mediate between our tissue formation and ordinary con- 

 nective tissue is met with. 



We now turn to the adipose tissue. 



True connective tissue, to the consideration of which we 

 shall soon arrive, appears partly as a firm, partly as a loose 

 texture. In the latter case^ as under the corium, under 



mucous and serous membranes, etc., it 

 encloses irregular communicating spaces. 

 These are frequently occupied by groups 

 of peculiar cells, overladen with fat. 

 This is fat tissue (Fig. 48, a). 



The cells appear large, measuring 

 0.076 to 0.13 mm., with nuclei of 0.076 

 to 0.009 mm. A thin covering closely en- 

 velops a single large drop of fat. The 

 latter, from its strong refractive power, 

 conceals the nucleus and the outlines of 

 the envelope. 



An appearance is thus caused as if 

 there were free drops of fat, with a dark 

 periphery by transmitted light, yellow- 

 ish, silvery and bright by incident illumination. Still, the 

 always considerable diameter, a slight polyhedral flattening 

 of the elements which are closely pressed together, avert the 

 mistake. Free fat forms spherical drops of every possible 

 size (b). 



The envelope, after its rupture and the escape of the con- 

 tents, may be demonstrated as a thin, collapsed sac (c), like- 

 wise in an intact condition, after drawing out the fatty con- 

 tents with alcohol or ether. The nucleus, lying quite excen- 

 trically, is readily recognized after tingeing with carmine. 



FlG. 48. — a, human fat cells, 

 lying together in groups ; b, 

 free glabules of fat ; c, empty 

 envelopes. 



