Multiple Staining, &c. By B. Wills Bichardson. 869 



time-test, however, has been rather short for more positive speaking 

 upon this point. 



Iodine-green, Stirling mentions,* has a great affinity for bone. 

 Confirmatory evidence as to the accuracy of this statement is 

 afibrded by those sections in which the iodine-green exceeded the 

 malachite in the green-stain, the recently formed bone being 

 stained dark bluish green. The nuclei of the cartilage cells of the 

 ossifying vertebra have a rich grey tint modified by their previous 

 carmine colouring. 



The sections exhibited at the club meeting were exposed to the 

 action of watery solutions of iodine and malachite-green dyes, in 

 different proportions, until they seemed dark blue in colour, in 

 the hope of obtaining stainings in varied shades of green, from the 

 nearly pure malachite to the deeper iodine-green. 



These experiments had the following results : — 



1. Picro-carmine stained section placed in equal parts of the 

 iodine and malachite-green solutions, diluted with water to make 

 them slightly transparent, shows the cartilage cells' nuclei of a 

 light purplish grey, the newly formed osseous walls of the cancellous 

 tissue being dark bluish green of extreme richness. 



2. Picro-carmine stained section — placed in the same green 

 fluid — in which ossification of the cartilage seemed completed ; the 

 walls of the cancellous tissue are similar in tint to those of No. 1, but 

 the spaces themselves are filled, almost without exception, by gor- 

 geously coloured corpuscles, in ruby and yellow. Outside or bound- 

 ing these central stainings of Nos. 1 and 2, many of the other 

 component structures of the section are differentiated with much 

 distinctness in picro-carmine and green, viz. : sections of muscles, 

 of tendons, and of hairs in their follicles. In some of the follicles, 

 two shades of green are visible, rendering these sections quadruple 

 stainings. 



3. Picro-carmine stained section placed in a shghtly diluted 

 mixture of the green dyes, in which the malachite was slightly in 

 excess ; the bone is dark bluish green at its circumference, the 

 latest formed bone being a lighter green. The other structures 

 of the section resemble Nos. 1 and 2 in colouring. 



4. Picro-carmine stained section submitted to the action of the 

 malachite-green only; the new bone is stained light green, but, to my 

 eye, it is not so strikingly effective a colour by transmitted hght, as 

 the mixed green colouring of the other structures. 



The hairs and hair follicles are a lighter green in tint than in 

 the other sections. In a few follicles some of the layers are a 

 delicate blue, rendering this section likewise, a quadruple staining. 



I had better observe that in staining animal tissues with iodine 

 and malachite-green dyes, when the sections have become tolerably 

 * ' Text-Book of Practical Histology,' p. xlvi. 



