GOLD METHOD. 



95 



of the metal in those parts of the tissue for which it has 

 the greatest affinity ; in the case of gold this is generally 

 the protoplasm of the cells (and the nerve-fibres, where 

 any exist) ; in the case of silver it is the ground substance, 

 or matrix, or intercellular substance ; so that the results 

 of the two processes may, at least in the case of the carti- 

 lage-cells, be looked upon as standing to each other in the 

 light of a positive and negative image, using the terms as 

 they are employed in photography. 



Fig. 19. 



Warming nppnrntns for maintaining portions of tissue, after treatment 

 by the gold method, at a constant, raised temperature. The lower 

 part of the apparatus is filled with water, into which the bulb of the 

 mercurial regulator dips. 



If it is the winter time, and especially if there is very 

 little bright sunlight, it is of the greatest importance to 



