10 



THE HUMAN BODY. 



descriptive anatomy under the name of fibres of the muscles. 

 The fibrils are contractile but not elastic, and their primitive 

 bundles have a homogeneous envelope of elastic but not 

 contractile tissue called sarcolemma. 



Fibrous tissue has the same ele- 

 ments as the cellular tissue, united 

 in compact bundles visible to the 

 naked eye, strongly adherent among 

 themselves, and interlaced in every 

 direction. Fibrous tissue is found 

 especially in the articulating and inter- 

 osseous ligaments and in certain en- 

 veloping membranes, as the sclerotic, 

 for example, which forms the white 

 of the eye. 



Tendinous and aponeurotic tissue 

 is made up of a variety of very thin 

 laminated fibres, with puckered edges, 

 undulated and adhering directly at 

 one extremity to the sarcolemma of 

 the striped muscular fascicles, and to 

 the osseous substance at the other. 

 These fibres unite in little flattened 

 polyhedral bundles, from 'ooi to "002 

 of a millimetre in breadth, from which 

 the tendons and aponeuroses, which 

 are of a tendinous nature, are formed. 

 Tendinous tissue is in extensible 

 lengthwise, and inelastic. 



Nervous tissue is essentially formed 

 of tubes, which are large and small. 

 They have homogeneous, thin, trans- 

 parent walls, and contain a viscous, 

 fatty fluid, which is the medullary substance or the whitr 

 substance of Schwann, in which there is a sort of stem the 

 axis-cylinder. In the spinal marrow and in the brain the 

 walls of the tube are wanting, and only the medullary sub- 

 stance and the axis-cylinder remain. As we approach the 

 outside of the body we find, on the contrary, that the tubes 



Fig. 5. Striped muscular tis- 

 sue as seen under the 

 microscope. 



A, Fibril deprived of the sar- 

 colemma, to show the disks 

 of which it is composed. 



A', One of these disks. 



B, Several fibres less magni- 

 fied. 



