442 XXXII. CELL-DIVISION AND NUCLEAR DIVISION. 



alcohol, pour the iodine-green into a saucer, and slowly add to 

 it the fuchsin solution until the fluid has taken a distinct violet 

 colour. The anther sections to be stained are placed on the 

 object-slide in a drop of this fluid, which, after the lapse of about a 

 minute, is run off by tilting the object-slide, and sucked up with 

 blotting-paper. A drop of glycerine is then placed upon the 

 object, the sections arranged, and covered with a cover-glass. 

 These sections show the cytoplasm red, the nuclear substance 

 blue, the nucleolus stained red ; the preparations are exceedingly 

 beautiful and instructive, though inferior in sharpness to those 

 obtained by more complicated methods described hereafter. They 

 can be closed with Canada balsam, and subsequently with gold 

 size. Canada balsam, however, as has been already mentioned 

 (p. 113), is soluble in the oils used for homogeneous immersion ; 

 care should therefore be taken not to allow the oil to remain in 

 contact with the balsam, and, after use, to wipe the oil off rapidly. 

 As the Canada balsam used in closing always runs under the 

 cover-glass a little, when it is used the object need not be pro- 

 tected in any other way from the pressure of the cover-glass. If 

 gold size alone is used for closing, it is recommended first to draw 

 two lines of gold size across the object-slide with the camel-hair 

 brush. These lines must be at such a distance that the cover- 

 glass will rest with its two edges upon them. The cover-glass is 

 first laid on when the lines are half dry. The line of gold size 

 drawn round the edge of the cover-glass must be laid on several 

 times, waiting till the previous layer is dry before putting on a 

 new one, and using for the purpose very dilute gold size, diluted 

 with linseed oil. The closure is complete when the preparation 

 held up against the light no longer shows lines of light at the edge 

 of the cover-glass. The object can be protected from the pressure 

 of the cover-glass in the simplest possible way, by laying in the 

 preparation hairs of sufficient thickness, or minute plates of mica. 

 Or, for the protection of objects, before laying the cover-glass 

 upon the object-slide, four spots of wax can be made upon it, by 

 means of the wick of a small wax candle which is temporarily 

 lighted and then put out again. Such wax candles can also be 

 used in order to make a temporary closing layer of wax at the 

 edge of a cover-glass already fixed by spots of wax at the 

 corners. 



In longitudinal sections through the anthers all the mother- 

 cells are not found in the same stage of division. The stages 



