168 PRACTICAL HISTOLOGY [XXI 



cells disappear more or less quickly, and the ovoid cells 

 become granular. (The central cell granules are not 

 preserved by most hardening agents, cp. 1.) 



4. Vertical section of the pyloric end of the 

 stomach. (Alcohol; hsematoxylin.) Compare these 

 with the sections made of the cardiac end. Note 



The greater thickness of the muscular layers. 



The wider and longer mouths to the pyloric gastric 

 glands, their more obvious branching, the absence of 

 ovoid cells (if the section passes through the beginning 

 of the pyloric region a few ovoid cells may be seen), the 

 short columnar cells of the bases of the glands and the 

 usually distinct lumina. (These are more distinct in 

 the dog than in the rabbit.) 



5. Examine fresh pyloric glands (cp. 3). The cells are 

 devoid of the distinct granules seen in the central cells of the 

 fundus. 



6. Section of cardiac region of stomach of frog (osmic acid). 

 Observe that the surface cells are in general features like those 

 of the mammalian stomach ; the necks of the glands have swollen 

 mucous cells ; the bodies of the glands have one kind of cell only, 

 in shape somewhat resembling the ovoid cells, but containing 

 distinct granules. (In lower vertebrates the granules of the fresh 

 gland-cells are preserved by osmic acid.) 



7. Transverse vertical section of the lower third of 

 a rabbit's oesophagus (potassium bichromate 1 p.c.). 

 Stain with hsematoxylin (or Ehrlich-Biondi fluid) 

 and compare it with the corresponding sections of the 

 stomach. Note the following points of contrast : 



The muscular coat contains striped as well as 

 unstriped muscular fibres ; sections from the upper part 

 of the oesophagus show no unstriped fibres. 



