I9 2 BOTANICAL MICROTECHNIQUE. 



ous .\% solution of fuchsin, then wash with water, stain 

 again with .2% aqueous solution of methylene blue, and 

 finally wash with alcohol or with a mixture of three parts 

 xylol and one part alcohol. 



3. Acid Fuchsin and Methylene Blue. The microtome sec- 

 tions fastened to the slide are stained for half an hour in a 

 .\% aqueous solution of acid fuchsin, then quickly rinsed 

 with water and treated for \-\ minute with a .2% aqueous 

 solution of methylene blue. The superfluous stain is then 

 removed with alcohol and the preparation, as soon as it is 

 air-dry, is extracted with clove-oil, in which it may be left 

 from 6 to 24 hours. The clove-oil is then washed out with 

 alcohol or xylol-alcohol, and the preparation finally mounted 

 in balsam. This method has also been used by Schott- 

 lander (I). He states, however, that the time of exposure 

 to the methylene blue must be much varied (between a few 

 seconds and two minutes). 



337. In many cases digestive fluids may be used for the 

 recognition of the chromatin-globules. These are not at- 

 tacked by pepsin, but are quickly dissolved by trypsin (cL 



232-4). 



338. I will remark here that Altmann (III) has observed 

 a granula-structure in the resting nucleus, which cannot 

 be further discussed here, since he has not published the 

 methods used by him. 



339. The nuclear membrane is also slightly capable of 

 staining. According to Fr. Schwarz (I, 123), it is best made 

 visible by a 20$ solution of common salt or of mono-potas- 

 sium sulphate, or by a concentrated solution of potassium 

 bichromate or the mixture of potassium ferrocyanide and 

 acetic acid mentioned in 238. 



III. The Kary 'o kinetic Figures. 



340. In nuclei in process of indirect or karyokinetic divis- 

 ion there may be distinguished a chromatic and an achro- 

 matic figure. The former generally consists of a nuclear 



