99 



carefully removed, and suspended for several days in alcohol, then 

 divided into small pieces, stained in borax carmine or Delafield's 

 luetnatoxylin, embedded in paraffin, and sectioned. Fix to the 

 sl'de, and mount in balsam. 



Study first under low power, and notice the bronchi, 

 blood vessels, and alveoli. The sections of the large 

 bronchi show a lining of stratified ciliated columnar epithe- 

 lium resting on a fibrous mucosa, in which small mucous 

 glands may be observed. Next, there is a band of non- 

 striped muscle tissue, outside of which cartilage plates may 

 be seen in cross-section. The small bronchi are lined by a 

 single layer of ciliated columnar cells, and the cartilaginous 

 plates are wanting. Try and make out the capillaries 

 between the alveoli ; a few blood cells may be seen in them. 

 Sketch a segment from the wall of a large bronchus ; also 

 a small bronchiole with a few of the surrounding alveoli, as 

 seen under high power. 



(g) Thyroid Gland. 



A piece of the thyroid gland of a dog was hardened in mercuric 

 chloride, embedded in paraffin, sectioned, and fixed to cover 

 glasses. The sections were then stained in hrematoxylin and 

 eosin, dehydrated, and cleared in oil of bergainot and xylol. Mount 

 on balsam. , 



Study first under low power. The gland is surrounded 

 by a fibrous capsule. Oval or round alveoli, lined by a 

 single layer of cubical cells, are seen. The alveoli are filled 

 with a substance which stains deeply in eosin. Sketch 

 several alveoli under high power. 



