376 The Microscope. 



around and in the specimen, which can then be cut without difl&ctilty. 

 The sections are then placed in water in order that the gum may be 

 dissolved out, when they are ready for staining. Stain with hsema- 

 toxylin and mount in balsam or glycerin. 



In the spongy portions of the cord, small masses of retiform or 

 reticular tissue may be studied. This tissue is a form of fibrous 

 tissue arranged, as its name denotes, in a network, composed of 

 rather cylindrical bundles of small fibers. At the various points 

 where the bundles seem to cross, a connective-tissue cell is generally 

 found. This cell is flat and stellate. Careful teasing will remove it 

 from the fibers on which it is placed. Thus isolated it can be studied 

 to the best advantage. It possesses a large, oval nucleus and has a 

 slightly graniilar appearance. The fibers composing the network 

 can be separated by teasing out a specimen which has remained for 

 some time in Mliller's fluid. They are quite similar to the fine fibers 

 of fibrous tissue already described. 



Adenoid Tissue. — This form of connective tissue can be best 

 studied in the lymphatic glands, where it is found in a pure state. 

 Harden such a gland, preferably one from an ox, in Mliller's fluid 

 and alcohol, make cross sections, stain lightly in hsematoxylin and 

 mount. 



The tissue will be seen to be composed of a very fine meshwork, 

 the interstices of which are packed with lymphoid cells. The mesh- 

 work is quite similar to that of reticular; tissue, in fact a perfect dis- 

 tinction between the two is impossible. The network is composed of 

 fibrils which are given off from thick trabecule, which traverse the 

 tissue in more or less parallel bands. These trabecule are derived 

 from the inner fibers of the capsule of the gland. 



The connective tissue corpuscles are found in the same position 

 as those of reticular tissue. They can be penciled off . and studied 

 separately. The network can be best studied in a specimen which 

 has been agitated for some time in a test-tube half full of water. 

 This removes the greater number of lymphoid cells and allows of a 

 clearer view of the framework. The lymphoid cells are quite iden- 

 tical with the leucocytes of the blood. When isolated from living 

 tissues they sometimes show amoeboid movements. Each contains a 

 weU- defined nucleus embedded in a granular cell body. 



Gelatinous Tissue. — This is essentially an embryonal tissue, and 

 is only found in the adult in the vitreous humor of the eye where it 

 is much changed from its embryonal form. The umbilical cord con- 

 tains large quantities of the pure tissue, where it can be studied in a 



