72 JOURNAL OF THE [July, 



it is first impregnated with the mordant and then brought into con- 

 tact with the stain. The tests which I have made, and the speci- 

 mens which are here for examination, amply prove this. They in- 

 clude a large number of specimens illustrating the action of the 

 different stains upon cotton and linen fabrics, and in some cases 

 upon woody fibres also. Some specimens show the effect of the 

 stains when used alone, while others show the effect of the same 

 stains when used in connection with different mordants. The 

 mounted preparations placed under the several microscopes show 

 the microscopic appearance of some typical specimens of these 

 stained fibres. 



Grenacher's Carmine is a solution of carmine in alum, which one 

 authority states will stain cellulose a fine red, but does not stain 

 lignified or suberized tissues. This clearly refers to cellulose as 

 it occurs in soft vegetable tissues, and the same doubtless applies 

 to the staining of cellulose as described in works on the subject. 

 Cotton and linen fibres which were immersed in this stain for 

 twelve hours and washed in water had only a slight reddish tint. 

 The fibres were then immersed in the stain for fifty-four hours 

 with no better result. 



Thiersch's Carmine is a solution of carmine with oxalic acid. 

 Cotton fibre was immersed in this stain for eighteen hours and 

 washed. It had a dull rose color, which was very faint when seen 

 in individual fibres as in the mounted preparation. 



Borax Carmine. — The rssult with this stain both upon cotton 

 and linen fibres was about the same as with Grenadier's carmine. 

 Oxalic acid was used as a "fixing" agent. 



Logwood and Brazilwood. — In the tests which were made with 

 these dyes I used a tincture obtained by soaking the chips in 

 strong alcohol, and filtering when necessary. 



As already stated, hrematoxylin, or logwood stain, can often be 

 used without a mordant in the staining of vegetable sections, but 

 when applied to cellulose fibres it is almost without action. 



A common preparation of haematoxylin for staining purposes is 

 its solution with alum. This is claimed to stain both cellulose 

 and lignified tissue, but not suberin. When cotton fibre is 

 immersed in this solution for four hours it is very fairly stained, 

 and when mounted in balsam has a light blue color. If the fibre 



