22 PRACTICAL HISTOLOGY [ill 



d. Towards the outside of the drop, where evapo- 

 ration is going on, many of the red corpuscles are 

 crenate. 



e. They are much smaller than the red corpuscles 

 of the frog. 



2. Observe the colourless corpuscles. Most are 

 larger than the red, they resemble in general appearance 

 the white corpuscles of the frog; to observe their 

 amoeboid movements a drop should be protected from 

 evaporation (Less. n. 2, e) and warmed to the 

 temperature of the body. 



Irrigate with *5 p.c. acetic acid (cp. Less. n. 5). 



a. The red corpuscles swell up and become 

 spherical, their haemoglobin is dissolved, leaving the 

 hardly visible stroma. (The same effect is produced 

 by water.) 



b. No nucleus is brought into view. 



c. In the white corpuscles the cell-substance be- 

 comes more transparent, and the nucleus comes into 

 view (cp. 3). 



3. Prepare two dry films of blood (cp. p. 14). 

 Place the cover-slips film uppermost on a slide, and 

 examine (h. p.) ; if there is a yellowish tinge of haemo- 

 globin between the corpuscles or if the outlines of the 

 red corpuscles are indistinct, the films should be thrown 

 away and fresh ones made. Stain one film with eosin 

 (cp. p. 15) and the other with eosin and methylerie blue 

 (cp. p. 16). 



