126 STUDENTS HISTOLOGY' 



away, should be hardened quickly in strong alcohol. Transverse sections can 

 be made free-hand, or the tissue may be infiltrated with paraffin or celloidin, 

 and cut with the microtome. Stain with hsematoxylin and eosin, and mount 

 in balsam. 



TRANSVERSE SECTION OF PORTION OF BRONCHUS OF PIG 



(Fig. 85) 



OBSERVE : 

 (L.) 



1. The epithelial lining: (a) The wavy course, (b) Regions 

 occupied by beaker or goblet cells. (The letter E in the drawing 

 leads to such a group, (c) The number of nuclei, indicating the 

 presence of more than a single layer of cells. 



2. The mucosa. (a) Deeply stained blue nuclei of the lym- 

 phoid (or adenoid) tissue just beneath the epithelium. (&) Pink 

 portion of the region below the lymphoid tissue. (The longitudi- 

 nal elastic fibers cut transversely.) (c) Blood-vessels. 



3. The muscular coat, (a) Apparent solution of continuity 

 in places caused by tubes of mucous glands. (&) The absence 

 of large vessels in this coat. 



4. The external layer, (a) Its extent. (It includes the 

 remainder of the section.) (6) Large cartilage plates, C, stained 

 blue, (c) Cartilage-cells. (Note their differing forms and dispo- 

 sition in rows next the surfaces of the plates.) (d) Perichondrium 

 stained pink. (e) Mucous gland -coils. (They are usually 

 between the cartilage and the muscular coat.) (/) Section of 

 bronchial arteries and veins, (g) Collections of adipose tissue 

 on the outer surface, (h) Portion or whole of pulmonary artery 

 and medullated nerve-trunks outside of and accompanying the 

 bronchus. 



(H.) 



5. Epithelial lining, (a) Cilia of columnar cells. (6) The 

 ovoid cells between the tapering columnar cells, (c) The "base- 

 ment membrane," upon which the columnar cells rest, (d) The 

 goblet or beaker cells. 



6. The mucosa. (a) The reticulum of the lymphoid tissue. 

 (It will appear only where the lymph -corpuscles have been acci- 

 dentally brushed out.) (&) The transversely divided ends of the 

 elastic fibers. (They appear as a pink mosaic.) (c) Capillaries. 

 (They may frequently be traced for a considerable distance in their 

 tortuous course.) 



