126 ELEMENTARY BIOLOGY. [CHAP. 



P. The cells ; irregular, flat, and close fitting. 



y. The cell structure and nucleus. 



8. Look for lymph stomata ; perforations of the 

 membrane, each surrounded by small more 

 deeply stained cells. 



Should the silver nitrate reaction fail, the 

 methylene blue process may be tried, as follows. 

 Place for 10-15 minutes in 4 per cent, solution 

 methylene blue. Transfer to saturated solution 

 of picrate of ammonia for half an hour ; wash in 

 the same and examine in weak glycerine. 

 d. Stratified epitlielium ; see epidermis 15. Hi. 



3. Connective tissue. 



Of this there are two main varieties, a. and b. 



a. White fibrous tissue. This occurs typically in 

 tendons, but is mixed with the other tissues. 

 Tease out a bit of fresh tendon in water : examine 

 with a high power. 



a. It is chiefly made up of very fine wavy fibres 

 which, in the aggregate, impart a glistening 

 white colour to the tissue (white fibres) ; they 

 run in parallel bundles and do not branch. 

 ft. Treat with dilute acetic acid. Most of the above 

 disappear, but a few well-defined curled fibres 

 (yellow elastic fibres) remain. Besides these 

 small irregular protoplasmic masses are brought 

 into view (connective-tissue corpuscles). 



b. Areolar tissue. Lay bare the muscles of the hind- 

 limb ; sheets of areolar tissue will be seen passing 

 between them and the integument. Remove one 

 of these, being careful to avoid undue stretching 

 and transfer to a slide : examine in water. 



