XXIX, 1. Rusk: A constant teiuperature oven for paraflin imbedding. 85 



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



A constant temperature oven for pai'aftin 



imbedding. 



By 

 G. Y. Rusk. 



With one figure. 



The distinctive feature of the oven described below was sug- 

 gested by seeing a constant temperature water bath , devised by 

 Professor F. F. 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. The 

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

 tridge such as is used in certaiu forms of flat iron, 



The apparatus consists of a box, constructed from heavy sheet 

 copper tinned on tlie inside, the dimensions which we employed 

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

 Chambers G ^4" X 11 ''//' X lO^//' (Z) and E). On the inner 

 walls of these are projections for shelves or for trays containing 

 paraflin. 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 

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

 with a retlux condenser, one of the Soxleth type answering admirably. 

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

 these are really not esseutial. 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 dirainishing heat loss. 



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



