ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



775 



eight copper vessels, containing, say, formalin, rising alcohols, clearing 

 fluid, and paraffin. The material to be prepared is placed in the cage k o, 

 and the cover e is lowered (as in fig. 112) so that the cage and its contents 

 are immersed in the formalin bath. The contact makers around the 

 margin of the clock are set so as to control the length of stay in each 



Fig. 112. 



bath. When the hand reaches the first stop, a contact is made ; this 

 sets in motion a mechanism which raises the carrier and turns it through 

 one-eighth of a circle so that the cage comes to rest above the next 

 bath. This position is shown in fig. 113. After a moment the con- 

 tact is again broken and the cover again descends. Thus each time the 

 clock-hand reaches a stop, the tissue is transferred to the next bath, 



