54 ELEMENTAET PHYSIOLOGY. [iV. 



lated with acetic acid ; leave it exposed to the 

 light. In one to two days, when it has hecome 

 a red-purple colour, mount it in glycerine. 

 Observe the cell-substance well coloured, and 

 hardly at all shrunken, the nuclei deeply coloured 

 and having a sharp outline, the matrix coloured 

 very slightly. 



4. Take a piece of rib cartilage from a recently 

 killed adult animal and with a razor cut thin 

 transverse sections' and transfer them with a 

 camel-hair brush to a watch-glass containing 

 normal salt solution. Mount one section in 

 normal salt solution and another in osmic acid 

 1 p.c; in the former observe under a high 

 power, that 



a. The cells frequently shew signs of partial 

 degeneration, containing fat globules which 

 may be nearly as large as the cell ; these are 

 very highly refractive and so have a very 

 distinct outline. 



I. In places the matrix may be fibrillated, and 

 in places semi-opaque owing to calcareous 

 deposit; irrigate with 1 p.c. hydrochloric 

 acid, the calcareous deposit is dissolved, but 

 the fibrillation is not affected (it differs thus 

 from the fibrillation of white fibrous connec- 

 tive tissue, cp. Lesson v. § 2 6). 



c. Indications of primary and secondary capsules 

 may be seen (cp. § 6). 



1 The section3 may be out with a freezing microtome, cf. Appendix. 



