774 DIRECTIONS FOR LABORATORY WORK 



a mammal (e.g., mouse, rabbit). As the fat cools note the formation of 

 margaris crystals. Add a drop of methylene blue and sketch (65) several 

 cells. Note shape and size of cell, position of nucleus, and character of 

 cytoplasm. Sketch (66) several cells from a teased specimen of fresh 

 fat preserved in osmic acid. What is the color of the fat globule ? Add 

 eosin stain and note cytoplasm, fat globule and nucleus. Sketch (67) 

 small area of fat in subcutaneous tissue from stained section of skin or 

 capsule of some gland, e.g., pancreas, kidney. Note position of nucleus, 

 and distribution of cytoplasm. What effect has alcohol and ether pres- 

 ervation on fat? Distinguish between nuclei of connective tissue and 

 fat cells. 



Sketch (68) developing adipose tissue from stained section of sub- 

 cutaneous tissue of young animal. (Developmental stages are commonly 

 to be found also in the areolar tissue enveloping the pancreas, kidney 

 and other viscera.) 



(2) LYMPHOID (Adenoid) TISSUE. (Modified reticular tissue.) 

 Study a stained section of a small lymph node. Note cortex and medulla. 

 Sketch (69) small area of medulla, including the denser tissue of the 

 medullary cords and the enveloping looser tissue of the sinuses. In the 

 sinuses the reticular tissue is especially prominent. 



(3) PIGMENTED CONNECTIVE TISSUE. (Modified areolar tissue.) 

 Study section of derma and subcutaneous tissue of negro skin ; or 

 the choroid coat (middle tunic) of the eye; (or toto mount of skin of 

 young salamander or lizard). Sketch (70) several pigment cells. Note 

 various irregular shapes of cells, and form and distribution of the pig- 

 ment granules (melanin granules). Does the nucleus contain pigment? 

 What is the distinction between a 'pigment cell' and a 'pigmented cell' ? 



(4) NOTOCHORDAL TISSUE. This is of entodermal origin (ecto- 

 dermal in the guinea pig; G. Carl Huber), and resembles con- 

 nective tissue only in its grosser features. It is represented in the adult 

 only in the nuclei pulposi of the intervertebral discs. Sketch (71) 

 small section of notochord from stained transverse section of a 10 to 20 

 mm. pig embryo. 



(5) NEUROGLIA. This is the connective tissue of the central nerv- 

 ous system (brain and spinal cord). It is of ectodermal origin. It 

 will be considered in connection with nervous tissues. 



(C) SUSTENTATIVE. 



(a) Cartilage (Gristle). 



(1) HYALINE. Make l.p. study of cartilage plate and enveloping 



