BY N. A. COBB. 159 



a long tine wire up and clown in the reservoii- for a few seconds. 

 The fiow, which at once commences drop-wise from the point of 

 tlie filter, should be so regulated, either by tijjping the instrument, 

 or by breaking off more or less of the capillary part of the filter, 

 as to cause the reservoir to be emptied in from two to five hours, 

 when the objects will of course be in 33 per cent, alcohol, having 

 been guarded to the utmost against diftusion currents. They are 

 now to be transferred to borax-carmine, a fluid heavier than 33 

 per cent, alcohol, by the use of reservoir a. Fill the long arm of 

 the reservoir with borax-carmine, and cork it, leaving the short 

 arm empty and open. Mix equal parts of carmine and 33 per 

 cent, alcohol (call this mixture 2). Mix equal parts of 2 and 

 carmine (call this 1). Mix equal parts of 2 and 33 per cent, 

 alcohol (call this 3). Add mixture 1 to the short arm of the 

 reservoir until it is one-fourth full, mixture 2 until it is half full, 

 mixture 3 until it is three-fourths full and till up with 33 per cent, 

 alcohol. Transfer the object-box and filter to a', avoiding bubbles, 

 and uncoi'k the long arm. The flow begins as before, but this 

 time ujjward through the object-box, and the objects are thus 

 transferred in from two to five hours to borax-carmine. 



After staining, the objects are transferred to 50 per cent, 

 alcohol by means of a reservoir a, the flow being so regulated that 

 the change takes {)lace in from ten to twenty hours. Then change 

 successively to acidulated 70 per cent., 90 per cent., and absolute 

 alcohol, allowing at least ten hours for each change. Transfer to 

 turpentine, chloroform, oil of cloves, or any oil desired by reser- 

 voir a'. Finally to thin balsam, still hy means of the differentiator. 



Whenever the objects are to be transferred to a lighter fluid, 

 use reservoir a ; whenever they are to be transferred to a heavier 

 fluid, use reservoir a. If objects are to be transferred to glycerine, 

 transfer first to 50 per cent, glycerine in twelve hours, and then 

 to pure glycerine in twenty-four hours. 



Objects' which defeat successful fixation by untimely contrac- 

 tions may be rendered insensible by means of the difierentiator, 

 and then fixed perfectlij outstretched. Transfer them in the 

 differentiator to alcohol of from 5 to 30 per cent, (or other 



