HANDBOOK OF PHYSIOLOGY. 



anterior elastic lamina, and Descemet's posterior elastic lamina, both in 

 the cornea. 



A certain number of flat connective tissue cells are found in the 



ground substance between the elastic 

 fibres which make up this variety of con- 

 nective tissue. 



(c.) Areolar Tissue. 

 Distribution. This variety has a very 

 wide distribution, and constitutes the 

 subcutaneous, subserous and submucous 

 tissue. It is found in the mucous mem- 

 branes, in the true skin, and in the outer 

 sheaths of the blood-vessels. It forms 

 sheaths for muscles, nerves, glands, and 

 the internal organs, and, penetrating into 

 their interior, supports and connects the 

 finest parts. 



Structure. To the naked eye it ap- 

 pears, when stretched out, as a fleecy, 

 white, and soft meshwork of fine fibrils, 

 with here and there wider films joining in 

 it, the whole tissue being evidently elastic. 

 The openness of the meshwork varies with the locality from which the 

 specimen is taken. Under the microscope it is found to be made up of fine 

 white fibres, which interlace in a most irregular manner, together with 



FIG. 35. Transverse section of 

 tendon from a cross section of the tail 

 of a rabbit, showing sheath, fibrous sep- 

 ta, and branched connective-tissue 

 corpuscles. The spaces left white in 

 the drawing represent the tendinous 

 fibres in transverse section, x 250. 

 (Klein.) 



FIG. 36. Magnified view of the areolar tissue (from different parts) treated with acetic acid. 

 The white filaments are no longer seen, and the yellow or elastic fibres with the nuclei come into 

 view. At c, elastic fibres wind round a bundle of white fibres, which, by the effect of the acid, is 

 swollen out between the turns. Some connective-tissue corpuscles are indistinctly represented in c. 

 (Sharpey.) 



a variable number of elastic fibres. On the addition of acetic acid, the 

 white fibres swell up, and become gelatinous in appearance (Fig. 36); 

 but as the elastic fibres resist the action of the acid, they may still be 



