462 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



provided with two handles, and an opening which is closed hermetically 

 by means of a screw. This heater is filled with acetate of soda. Be- 

 sides the door there is only one aperture, that for the thermometer. 

 The apparatus is easily put into working order. The heater is put into 

 boiling water for 30, 45 or 60 minutes, according as it is desired to 

 keep up the temperature for 24, 36 or 48 hours. After the boiling is 

 finished the heater is wiped and put into the incubator. 



The apparatus will accommodate about twenty-four test-tubes placed 

 in a suitable stand. If the stand be not used it is advisable to put 

 some cardboard on the heater. 



The apparatus may also be used as a heat reservoir, by boiling the 

 heater for an hour, and afterwards further heating it over a spirit-lamp 

 until the temperature is above 100° C. The heater is then placed in 

 the incubator, care being taken not to shake it. When required for use 



iiil'" ' iiiiiiViiijjjiijjiiili! 1 ' 1 



the heater is shaken, and if this do not suffice, an iron wire is inserted 

 through the screw-hole and the contents stirred up. The heater in- 

 stantly becomes warm. In this way the apparatus can be got ready 

 some time before it is required for use. A list of the commoner patho- 

 genic organisms which have been cultivated successfully by, means of 

 this apparatus is given. 



Electrically Heated Incubator.* — F. Llanfland has devised an in- 

 cubator which is heated and regulated by the electric current. In the 

 water-jacket are inserted a number of copper tubes in which the heaters 

 connected by wires from the battery are placed. The regulating apparatus 

 consists of an electromagnet which actuates a mercury break by means 

 of a lever when the temperature rises higher than that .for which the 

 regulator is set. 



* Zeitschr.jf. wiss. Mikr., xvh. (1900) pp. 440-2 (l,fig.)- 



