92 PRACTICAL HISTOLOGY. 



specimens, which are left rather longer in the liquid, 

 the bone in the neighborhood of the cartilage is 

 softened, and the cartilage-cells are more colored by 

 the acid, and consequently more apparent. When 

 it is desired to prepare the tissue for the microscope, 

 one of the halves is taken from the fluid, washed in 

 water for a minute or two, and then, the bone being 

 held in the hand, one or two thin sections are taken 

 from the surface of cleavage vertically to the articu- 

 lar surface and extending through the whole depth 

 of the cartilage, including, if possible, a little of the 

 adjacent bone. The sections are placed in water on 

 a slide and covered, and are examined, first with a 

 low power to see the general arrangement of the 

 cartilage cell groups in the superficial, intermediate 

 and deep strata respectively, and subsequently with 

 a high power to see the intimate structure of the 

 cells. These should, as before indicated, present as 

 nearly as possible the same appearance as during life, 

 the only difference being that the tissue generally is 

 less transparent, and slightly colored, and that the 

 cell-outlines are rather more strongly marked. These 

 differences become even less obvious when glycerine 

 has been permitted to diffuse itself under the cover- 

 glass, for the preservation of the specimen. 



Sections are next to be taken parallel to the articu- 

 lar surface and mounted in the same manner; but 

 it must be borne in mind that it is only those sec- 

 tions which include parts of the cartilage near the 

 natural or artificial surface which will be of value 

 as respects the preservation of the tissue elements in 

 their natural condition, at least in the case of thick 

 articular cartilages of large animals. For the preser- 

 vative solution naturally takes some time to perme- 

 ate the cartilaginous matrix, and before it has time 

 to penetrate to the deeper parts, the cells will have 

 already shrunk away from the walls of the inclosing 

 cavities and have become changed in the manner 

 previously indicated. So that the deeper sections 

 will exhibit merely the irregular, contracted, and 



