CULTIVATIONS AT HIGHER TEMPERATURES. 83 



of which water is poured. At one corner of the box 

 a thermometer is immersed in the water, at another a 

 Reichert's thermo-regulator is placed, the construction 

 of which, it may be assumed, is known, and which is 

 able to regulate the temperature of the contents of the 

 box very exactly. The incubator is placed upon an 



Fig. 6. 



iron stand, which must be tall enough to leave a 

 space of about 10 cm. high between the flame of the 

 heating apparatus and bottom of tlie incubator. If 

 the distance is less, not only is the heating uneven but 

 the incubator, which, as a rule, is made of sheet zinc, 

 suffers. Koch's safety lamps or micro-burners are the 

 best for this purpose ; but if necessary, small paraffin 

 lamps without cylinders may be employed (Fig. 6). 

 Before making use of the incubator, it must be care- 



