xiii.] THE FROG. *n 



a. The red corpuscles. 



a. Their form : oval when seen in front face ; 

 almost linear in profile but slightly swollen at 

 the centre. 



ft. Their size: their length, breadth, and thick- 

 ness; measure. 



y. Their colour: pale yellow, when seen indivi- 

 dually; redder if a thick mass of them is 

 looked at. 



S. Their structure: they are homogeneous for 

 the most part, but possess a round granular 

 central nucleus. 



. Treat with water; they swell up and become 

 more spherical ; tfceir colouring matter is gra- 

 dually discharged; the nucleus is rendered 

 very evident, and ultimately all the rest of the 

 corpuscle disappears. 



. Treat with dilute acetic acid; results same 

 as with water, but produced more rapidly. 



b. Tho white corpuscles. 



Less numerous than the red : their colour, size, 

 granular character, nucleus, and changes of form 

 (amoeboid movements}-, see III. B. 



D. THE EXAMINATION OF A PREPARED SKELETON. 



The skeleton of a Frog may be prepared for ex- 

 amination by removing the viscera from the body, 

 and roughly dissecting away the nwscles, &c. Then 

 place the remainder in water and let it macerate 

 for about a week ; afterwards carefully pick away 

 the soft parts, with forceps, from the bones and carti- 

 lages. 



142 



