BROOK OR SPECKLED TROUT. 97 



a length of time, by changing the water occa- 

 sionally. 



This cell is made by taking two pieces of 

 thin plate glass of about three inches in length 

 by one inch in width, and between these is 

 placed a piece of cork or wood about the same 

 size, and about one-eighth of an inch in thick- 

 ness. These three pieces are to be cemented 

 together by means of gum shellac dissolved in 

 alcohol. Before cementing them together, how- 

 ever, the cork or wood, whichever it may be, 

 should all be cut away, except enough to close 

 the two ends and one edge of the two pieces of 

 glass, thus forming a cell, the two sides of wfyich 

 is formed of the plate glass, and the ends and 

 bottom are formed of cork or wood. The cell 

 stands upon its edge and is to be filled with 

 water, into which is placed the young fish or 

 the eggs to be examined. The microscope, of 

 course, must be placed in a horizontal position, 

 with a strong gas or lamp light in front of the 

 cell containing the fish or eggs, and the view 

 will be most satisfactory. 



I made some very interesting experiments by 

 means of the foregoing fixtures, on young trout. 

 After wounding the fish in some part, he was 

 placed before the microscope in the cell, and the 

 recuperative process could be plainly seen, from 



