464 Journal of Applied Microscopy. 



melted. If the right quantity has been used the objects will not slide out, or if 

 they become displaced push them back again with a slip of pointed paper slightly 

 moistened in the mouth. If the glycerine jelly becomes too thick by repeated 

 heating, or from other cause, add a small quantity of filtered water. 

 Cottage City, Mass. J. D. KiNG, Ph. D. 



Method for Sectioning Eggs Containing Much Yolk. 



Anyone who has worked upon eggs containing a great deal of yolk has probably 

 encountered the difficulty of the yolk globules falling out of the section during the 

 cutting, if the specimen has been imbedded in paraffin. To avoid this difficulty 

 without having to resort to imbedding in celloidin, Hertwig used a method which 

 has not, to my knowledge, been published. The stained specimen is imbedded in 

 paraffin by the usual method, mounted upon the sectioning block, and upon the 

 surface to be cut, a small drop of very thin collodion is placed ; the greater part of 

 the drop is then removed by gently touching it with the finger. Before cutting, 

 it is necessary to wait a moment until the ether has evaporated, which may be 

 hastened by blowing upon it once or twice. The section can then be cut with 

 any ordinary paraffin knife, and thinner than if it had been imbedded in celloi- 

 din. The collodion must be applied in the manner described after each cut. 

 Care must be taken not to have the layer of collodion too thick, or the section 

 will wrinkle badly. A very thin layer suffices to hold the yolk globules in place. 

 The sections are fixed to the slide, cleared and mounted by the ordinary paraffin 

 methods. The advantages offered by the described method are : the section may 

 be cut with any microtome knife or razor ; it is not necessary to flood the knife 

 with alcohol before cutting, and much thinner sections can- be made by a less 

 skilled workman. Clara Langenbeck. 



Wells College, Aurora, N. Y. 



A Convenient Method of Cleaning the Percentage Tubes 

 of the Haematokrit. 



In using the percentage tubes of the haematokrit, it is absolutely necessary 

 that they be perfectly clean. Since they have so small a bore, it is evident that 

 they cannot be cleaned by any ordinary process. In the laboratories of Purdue 

 University, the method used is as follows : immediately after making a count, the 

 tubes are placed in a dish of water for a few moments. This serves to loosen up 

 what blood there may be in them. A horsehair loop, containing a thread, is then 

 run through the lumen of the tubes. It has been found convenient to use this 

 horsehair loop, as it is stiff enough, and of sufficient strength to carry the thread 

 through. A needle might be used, but it is easier and takes less time to slip the 

 thread through this loop than to thread the needle. After the tubes have been 

 cleaned by the thread, it is necessary to dry them. In drying, a small bicycle 

 pump, with a piece of rubber tubing fitted over the nipple to hold the tubes, is 

 employed. In this way the tubes can be dried without any moisture getting into 

 them. Both tubes can be cleaned and dried within five minutes, or less. 

 Purdue University. CharlES S. BosenburY. 



