1 08 



PRACTICAL HISTOLOGY. 



[n. 



and granular, while the outline of the corpuscle may become very 

 indistinct (fig. 63). The nucleus appears somewhat shrunken or 

 shrivelled. If the corpuscles are roughly treated, the nucleus may 

 be seen placed excentrically, or even extruded from the corpuscle. 

 The acid acts on the haemoglobin, forming a new compound, which 

 diffuses out of the corpuscles and stains the surrounding plasma a 

 faint yellow. The nucleus in some of the corpuscles may absorb 

 some of the yellow pigment, and become stained thereby, especially 

 if a strong solution of acid has been used. The action on the 

 colourless corpuscles is referred to at p. 112. 



3. Dilute Hydrochloric Acid, i per cent. (H). 



(.) To a fresh drop of blood add, as before, a drop or two of 

 dilute hydrochloric acid. Watch diligently one or two of the red 

 corpuscles. They gradually enlarge, become spherical, and may all 

 of a sudden burst and discharge their contents, the nucleus coming 

 clearly into view during the process. After the rupture, the residue 

 of the stroma of the corpuscles may be seen in the field. In other 

 cases the corpuscles become clear, globular, and transparent, with 



FIG. 63. Frog's Red 

 Blood - Corpuscle 

 acted on by Dilute 

 A.cetic Acid, x 300. 



FIG. 64. Action of 

 Water on an Am- 

 phibian Coloured 

 Blood-Corpuscle. 



FIG. 6 5 . Action of 

 Syrup on Frog's 

 Red Blood - Cor- 

 puscle, x 300. 



here and there fine shreds stretching between the nucleus and the 

 surface of the spherical corpuscle. 



4. Water (H). To a fresh preparation of blood apply a drop of 

 water to the edge of the cover-glass, and notice its effects upon the 

 corpuscles. 



(a.) The water rapidly diffuses into the corpuscles and renders 

 them spherical, while at the same time it decolorises them, the 

 haemoglobin diffusing outwards into the plasma, and staining it 

 slightly yellow. The nucleus also becomes spherical. Thus the 

 outline of the corpuscles becomes very faint in the field of the 

 microscope, the corpuscles themselves now almost consisting of a 

 nucleated stroma (fig. 64). 



5. Strong Syrup (H). Place a small drop of blood on a slide 

 and near it a drop of syrup ; mix the two with a needle, and apply 

 a cover-glass. 



(a.) Observe that some of the red corpuscles are rapidly 

 shrivelled and puckered, especially when seen on edge, owing to 

 fluid passing out of them by exosmosis (fig. 65). Some of them 



