14 Harry C. Schmeisser. 



Lung. Presents a characteristic structure, entirely different from 

 that in the human lung. The tubules mentioned in the macroscopical 

 description are seen in cross, oblique, or longitudinal section, forming 

 large polyhedral units with wide walls composed of capillaries. The 

 intercapillary air spaces communicate with each other and with a large 

 central lumen. The latter is lined with a narrow band of smooth 

 muscles surmounted by endothelium, frequently cuboidal. The inter- 

 tubular fibrous tissue is small in amount, and contains large blood- 

 vessels, whose branches extend into the capillary bed. These structures 

 are closely packed with red blood cells. Only occasionally does one see a 

 lymphocyte. The bronchi resemble those of the human lung. Follicles 

 of lymphoid cells are frequently found in the submucosa or outside of 

 the bronchi near arteries. 



Bone-marrow. A low-power picture is very similar to human resting 

 marrow, i. e. } one sees a framework of fatty tissue inclosing nests of 

 marrow cells. Arteries are filled solely with red blood cells. Venous 

 spaces are difficult to determine.. 



Classification of Marrow Cells. Very thin paraffin sections were 

 stained with haematoxylin and eosin and studied under the oil- 

 immersion lens. The same cells appear slightly different under these 

 conditions than when seen in the Wilson smears of normal and leukaemic 

 blood. 



Erythrocytes. 



1. Normocyte (a) : Elongated, varying in shape, due to pressure. 

 Nucleus a solid, black rod or dot (longitudinal or cross section). 

 Cytoplasm yellowish-pink and glassy. 



2. Normoblast (6) : Eound, diameter about width of normocyte. 

 Nucleus round, uniformly black. Cytoplasm pink or faintly blue, and 

 glassy. Frequently a narrow clear zone is seen about the nucleus. 



3. Megaloblast (6) : Same, larger, about length of a normocyte. 

 Nucleus slightly picnotic. 



Leucocytes. 



1. Polymorphonuclear myelocyte with eosinophilic rods * (c) : 

 Round, Nucleus, two or more solid black lobes. Cytoplasm colorless 

 with bright red, spindle-shaped rods. 



* These are obviously the polymorphonuclear with eosinophilic rods, the 

 polymorphonuclear with eosinophilic granules and the large mononuclear 

 cell of the normal blood. 



