74 JOURNAL OF THE [July, 



lignified fibres can be obtained by means of the anilin colors. 

 In my experience, however, the staining of lignified fibres is not 

 in all cases as uniform as is desirable. 



When applied without a mordant, the fibre is only slightly 

 stained, and a mordant is therefore necessary in order to obtain a 

 stain sufficiently deep and permanent. 



In some cases this may be effected by staining first and then 

 mordanting, but, as already stated, it is better in the staining of 

 fibres to reverse this order and apply the mordant first. In this 

 way the staining may be effected in less time and the fibre be 

 more deeply stained. 



The method of mordanting the fibre was as follows : It was 

 first immersed in a ten per cent solution of tannic acid for about 

 an hour, the excess squeezed out, then placed in a one per cent 

 solution of stannate of soda for about thirty minutes, transferred 

 to water acidulated with sulphuric acid for a moment, washed in 

 water, and placed in the stain for fifteen to thirty minutes, and 

 finally well washed. The times here given for the action of the 

 different solutions can be shortened in many cases. 



A solution of tartar emetic, or tartrate of antimony and potash, 

 was substituted in some experiments for the stannate of soda, but 

 I think the latter is to be preferred for the reason that the tartrate 

 solution soon develops fungous growths. 



The list of anilin colors available for staining purposes is quite 

 a long one. I have tried some six or eight of these, but will refer 

 to only four, all of which have given good results and furnish all 

 needed variety in c?olor. 



These stains were tried with cotton, linen, and spruce fibres^ 

 and the mixed fibre obtained from a sample of filter paper, and 

 the specimens and slides here show the results obtained. 



Fuchsin. — This was used in an aqueous solution containing 

 0.25 gramme in 100 c.c. of water. 



I may mention parenthetically that this stain when properly 

 applied is the best material I have found for staining wool fibres 

 so as to bring out distinctly the structure of the scales. A slide 

 containing some of these stained fibres will be found under one 

 of the microscopes. 



Hofmanns Violet. — This was used in a strong alcoholic solu- 

 tion. Unmordanted cotton fibre is stained a very light blue, 



