52 THE CHEMISTRY A.AD PHYSICS OF THE CELL 



in SO far as a cement substance is required, and the cells generally lie 

 in almost immediate apposition. It is probable that there is a greater 

 or less amount of cement substance, even between the most closely 

 applied cells, and this substance seems to be related to mucin. It 

 (;an generally be brought out by staining with silver nitrate, and 

 ]\racallum ^" points out that this reaction is merely a micro-chemical 

 test for chlorides, and indicates that the cement substance contains 

 them in larger proportion than does the cytoplasm. 



42 Proceedings of the Royal Society, 1905 (76), 217. 



