and Laboratory Methods. 



1967 



A Simple Fixing Oven for Blood Preparations. 



In order to obtain satisfactory and uniform results in the staining of blood 

 spreads, it is necessary that the specimen be properly fixed before staining, 

 as the reaction to stains varies with the method and degree of fixation. 

 Some stains require 

 special methods of fixa- 

 tion, for which no 

 special apparatus is ne- 

 cessary, but for general 

 work fixation by heat 

 is preferable and, with 

 some stains, necessary. 

 Ehrlich's triacid mix- 

 ture, or some modifica- 

 tion of the same, is 

 without doubt the most 

 generally useful blood 

 stain now in use, and 

 requires fixation of the 

 blood film by heat for 

 the best results. 



For heat fixation 



Fig. 1. — A Simple Fixing Oven for Blood Preparations. 



the copper plate or bar is far from being satisfactory ; some spreads will be 

 overheated, some underheated, while a few will be subjected to the right tem- 

 perature. It is difficult to determine the proper length of time to apply the 

 heat, and, at best, but a few specimens can be fixed at a time. By this method 



it is very difficult to obtain 

 reliable and uniform re- 

 sults. 



The sterilizing oven 

 gives perfect results, but 

 is comparatively expensive 

 and for such work is slow 

 and not economical. Very 

 few general practitioners 

 possess such an oven and 

 for those who do not do 

 general laboratory work it 

 is an unnecessary adjunct. 

 Failing to find any 

 special apparatus listed 

 for heat fixation of blood spreads, I devised a small oven for the purpose and 

 had it made by a tinsmith. The apparatus is so convenient and satisfactory 

 that it occured to me that it might be worth while to send a description of it to 

 the Journal for the convenience of others who do blood work. 



Fig. 2. — The Oven opened; showing Tray for Cover-glasses. 



