56 



fi. MARSH ON BLEACHING AND 



of chlorine (or strictly speaking of euchlorine) will be observed to 

 fill the bottle B, whence it will pass along the connecting tube into 

 the water contained in the bottle A, and effectually and safely 

 bleach the sections. When the water becomes supersaturated, the 

 excess of chlorine will accumulate in the bottle above the liquid and 

 find an exit through the notch in the cork. As to the time 

 required for bleaching, this, of course, will vary in accordance with 

 the nature of the sections operated upon. As a rule, I set the 

 apparatus to work at night, putting it out of doors in a covered 

 place to avoid the smell of escaping chlorine, and in the morning 

 the bleaching is generally found to be complete — if not, further 

 time may be allowed without any danger to the sections being 

 incurred. 



Decolouration having been effected, nothing now remains but 

 thoroughly to wash the sections, for it is necessary to eliminate all 

 trace of chlorine before employing any staining agent. The usual 

 method of effecting this is to put the sections into a large basinful 

 of water, and repeatedly to change the water. As this process is 



