132 ELEMKNTAKV BIOLOGY. [CHAP. 



a. Connective tissue elements. 



/3. Ripe fat cells ; obvious as aggregates of large 

 highly refractive globules i^fat globules) of which 

 the tissue is chiefly composed. 



Note their optical characters, under different 

 levels of focus. 



y. Immature fat cells ; smaller irregular or rounded 

 cells, each lodging one or more fat drops. 



b. Preserve in spirit ; stain with haematoxylin. Ex- 

 amine the ripe cells under a high power; each 

 consists of — 



a. The fat globule ; apparent as a clear space, 

 which may or may not contain crystals. 



p. The cell membrayie ; deeply stained and more or 

 less granular, forming a thin envelope for a. 



y. The nucleus ; oval and compressed, buried up 

 in the cell membrane and usually surrounded 

 by granular protoplasm. 



8. Immature fat cells; look for those showing 

 stages in the formation of the fat globule. 



7. Unstriped muscle. 



a. Place a small piece of the muscular coat of the 

 intestine in Miiller's fluid for 2 — 3 days. Tease 

 up in hrematoxylin solution and examine under a 

 higli power. 



a. The muscle-cells ; elongated and fusiform, in 

 close apposition with each other; protoplasm 

 granular. 



^. Nucleus ; fusiform or ovoidal, generally situated 

 near the middle of the cell. 



