22 ART. 14-K. YEXDO: 



secondary lamella : the walls of the genicular cells, the greater part of 

 which is built up with the secondary lamella, contracting much more 

 than the articular cells during the process of the preparation. 



The middle lamella at the genicular portion proper stains 

 intensely with ruthenium red, in the same degree as the apparent 

 space just mentioned above. There is no doubt that both parts are 

 continuous, although they are in some species entirely interrupted at 

 the critical points. The space between the extragenicular portion of 

 the cells is continuous to the intercellular spaces at the articular 

 portion. 



When a section of Amp. tuberculosa is stained in hematoxylin 

 for a long time, say 21 hours in Boemer's, and treated with acetic 

 acid thoroughly, we have a preparation stained in a contrary manner. 

 The easily stained portions are easily washed away by the acid, and 

 the articular cells which are hard to stain in the usual method now 

 appear in a rather deep colour. The primary cellwall at the trans- 

 itional point remains almost unstained and the distal ends of the 

 extragenicular portion stain in the same degree with the articular 

 cells. This fact shows something different in the properties of the 

 primary cellwall in the transitional part and in the distal end of the 

 extragenicular portion. 



In this sort of preparation, the part of the primary cellwall in 

 contact with the space mentioned stains intensely, cf. hg. 4. When 

 treated with safranin the part now stained deep gains a yellowish 

 colour. 



It would not be useless to give some brief account of the middle 

 lamella of the articular cells. The middle lamella of the extragenicular 

 portion is practically continuous with that of the articular cells. When 

 stained with ruthenium red, the part in connection with the genicular 

 cells stains in the highest degree, The middle lamella of the articular 



