HARDWICKE'S SCIENCE-GOSSIP. 



TS 



DOUBLE STAINING OF WOOD AND OTHER VEGETABLE 



SECTIONS. 



By GEORGE D. BEATTY, M.D. 



my paper on 

 Vegetable 

 Staining iu the 

 January num- 

 ber of this 

 Journal, I said 

 the only aniline 

 colour I had 

 used with suc- 

 cess for staining leaves was 

 the blue. The statement 

 was based on the fact that 

 this colour did not come out 

 when the leaves were put 

 into absolute alcohol, or into 

 oil of cloves, provided cer- 

 tain brands of these chemi- 

 cals were used. 



I have lately discovered 

 that benzole fixes the ani- 

 lines when they are used 

 in staining vegetable and 

 animal tissues. It not only instantly fixes any 

 aniline colour iu vegetable tissues, but also renders 

 them as transparent as oil of cloves. 



Finding that benzole possessed this property, led 

 me to try double staining upon sections of leaves 

 and sections of wood. The results have proved 

 highly satisfactory. I have found the following 

 processes successful: — A section, say of wood, 

 being prepared for dyeing, is put for five or ten 

 minutes in an alcoholic solution of "Roseine Pure" 

 (Magenta), one-eighth or one- quarter of a grain to 

 the ounce. From this it is removed to a solution 

 of " Nicholson's Soluble Blue Pure," one balf- grain 

 to the ounce of alcohol, acidulated with one drop 

 of nitric acid. In this it should be kept for thirty 

 or ninety seconds, rarely longer. It should be fre- 

 No. 124. 



quently removed with forceps during this period, 

 and held to the light for examination, so that the 

 moment for final removal and putting into benzoic 

 be not missed. After a little practice the eye will 

 accurately determine the time for removal. 



Before placing the object in benzole it is well to 

 hold it in the forceps for a few seconds, letting the 

 end touch some clean surface, that the dye may 

 drip off, and the object may become partially dry. 

 By doing this, fewer particles of insoluble dye rise 

 to the surface of the benzole, iu which the brushing 

 is done to remove foreign matter. The object 

 should then be put into clean benzole. In this it 

 may be examined under the glass. If it is found 

 that it has been kept in the blue too short a time, 

 it should be thoroughly dried, and, after dipping in 

 alcohol, be returned to that dye. If a section of 

 leaf or other soft tissue be under treatment, it 

 should be put in turpentine or oil of juniper, as they 

 do not contract so much as benzole. 



When haematoxylon is used instead of magenta, 

 it is followed by the blue as just described. As 

 neither of these dyes comes out in alcohol or in oil 

 of cloves, the section may be kept in the former for 

 a short time before placing in the latter. 



The ha3matoxylon dye I prefer, is prepared by 

 triturating in a mortar for about ten minutes two 

 drachms of ground Campeachy wood with one 

 ounce of absolute alcohol, setting it aside for twelve 

 hours, well covered, triturating again and filtering. 

 Ten drops of this are added to forty drops of a 

 solution of alum ; twenty grains to the ounce of 

 water. After one hour the mixture is filtered. 



Into this the section, previously soaked in alum- 

 water, is placed for two or three hours, or until 

 dyed of a moderately dark shade. When dyed of the 

 depth of shade desired, which is determined by 

 dipping it in alum-water, the section is successively 



E 



