XXIX, 1, Rusk: A constant temperutuie oven for paraftin iiubedding. 85 



[Froin the Hearst Laboratory of Pathology, University of California. 



A constant temperature oven for paraftin 



imbedcling. 



By 

 G. Y. Rusk. 



With one figure. 



The distinctive feature of tlie oven described below was sug- 

 gested by seeing a constant temperature water bath, devised by 

 Professor F. P. Gay^ for inactivating sera. This feature consists 

 in the use of acetone , which has a boiling point of 56'2*' C, to 

 maintain a constant temperature throughout the apparatus. Tlie 

 heating of the oven is provided for by means of an electric car- 

 tridge sucli as is used in certain forms of fiat iron, 



The apparatus consists of a box, constructed from heavy sheet 

 copper tinned on the inside , the dimensions which we employed 

 being 17" X 15" X 12" (A). In the front of this are sunk two 

 Chambers G^jJ' X ll'^^j^" X lO'^l^" (D and E). On the inner 

 walls of these are projections for shelves or for trays containing 

 paraffin. D represents a closed door which has been omitted on 

 the other side to show the inside arrangement. Into the Space 

 between the outside wall and the sunken Chambers acetone is poured 

 throngh the opening just below A. This opening is then provided 

 witli a reflux condenser, one of the Soxleth type answering admirably. 

 Into the Chambers D and E are openings for thermometers, though 

 these are really not essential. Near the base of the side B is a 

 cylinder F designed to contain the heating electric cartridge snugly. 

 C is a cross-section of the door showing details of construction, 

 which is so reinforced to give rigidity and also to provide an air 

 Space, thus diminishing heat loss. 



^) Gay, f. f., Journ. med. Research, n. ser. vol. XIV, 1908, p. 73. 



