AMCEB01D PHENOMENA OF COLOURLESS CORPUSCLES 17 



applied. To ascertain that the right temperature is got and maintained, put 

 two pieces of paraffin, one melting at 35 C. (95 F.) and another at 38 C. 

 (100 F.), on the slide, one on either side of the preparation. The tempera- 

 ture must be such that the first piece is melted and remains so whilst the 

 second remains solid. 1 



2. Mount a drop of newt's blood diluted with an equal amount of salt 

 solution, and examine it in the same manner upon the copper stage ; the 

 temperature must, however, be kept below 30 C. Observe the effect of heat 

 in accelerating the amosboid movements of the pale corpuscles. Sketch one 

 at intervals of a minute (a) in the cold, (6) whilst warmed. 



3. Examine some yeast which has been mixed with salt solution. Observe 

 the yeast-cells or torulae, some of them budding. Sketch two or three. 



Now mix a little of the yeast and salt solution with a fresh drop of newt's 

 blood, oiling the edge of the cover-glass as before. Endeavour to observe the 

 inception of torulse by the white corpuscles. Sketch one or two corpuscles 

 containing torulae. 



Milk-globules or particles of carbon or of vermilion may also be used for 

 this experiment, but the process of inception is most readily observed with 

 the yeast particles. 



4. At the commencement of the lesson collect a drop of newt's blood into 

 a fine capillary tube, seal the ends of the tube, and mount it in a drop of oil 

 of cloves. Towards the end of the lesson examine it again to see white cor- 

 puscles emigrating from the shrunken clot (see fig. 16). 



FIG. 16. WHITE CORPUSCLES OF FROG'S BLOOD MIGRATED FROM SHRUNKEN 

 CLOT WITHIN A CAPILLARY TUBE. 



1 For exact work, an apparatus somewhat more complex than the above is re- 

 quired. For description of such a one see A Course of Practical Histology, pp. 22, 23. 



C 



