1894.] MICROSCOPICAL JOURNAL. 135 



Studies of the Histology of Various Mammalian Tissues.— II. 



By henry L. OSBORN, 



st. paul, minn. 

 Continued from page 70. 

 THE ALIMENTARY OANAL. 



In preparing the stomach or intestine for sections it is 

 important that a clean surface of the inner lining be ex- 

 posed to the action of the reagents used in preservation, 

 this can be attained by carefully washing the inner sur- 

 face of the organ with slightly warmed salt solution, 

 made by dissolving six parts of common salt in one thou- 

 sand of water. Pure distilled water should not be used 

 as it causes rupture of the wall of the cells and thus de- 

 stroys their natural shapes. After the surface is thus 

 cleaned pieces should be hardened either by the alcohol 

 method which is perhaps the most convenient or if pre- 

 ferred by the chromic acid, or other common mode. In- 

 jected specimens are necessary to give one a realizing 

 sense of the structure, specimens injected with a gelatine 

 mass can be hardened in the ordinary way for non-in- 

 jected tissues and have the advantage of preserving and 

 displaying both the vascular arrangements and the cell 

 structure. 



The alimentary tube presents a roughly similar con- 

 struction in all parts, but is different both structurally 

 and physiologically in different places in its details. It 

 is in general a double tube one inside the other, the 

 outer tube is muscular the inner one is composed of 

 gland-cells, between the two is a connective tissue coat 

 in which the principal nerves and blood-vessels run. 

 The three layers are known as the muscular, the sub- 

 mucous and the mucous coats named in their order from 

 the outside inward. The mucous and the muscular are 

 the active agents in the work of the organ while the mid- 

 dle coat is merely accessory. In addition to the organs 



