A New Growing Cell By A. A. C. Eliot Merlin. 19 



3. "When warm water from a thermostatic regulator is allowed 

 to circulate through the tank (to which a thermometer can be 

 adapted), living organisms can be kept for long periods at a given 

 temperature. In this case the metal under-part of the tank should 

 not rest on the Microscope stage, but two thin strips of ebonite or 

 other suitable non-conducting material should be inserted between 

 the box and the stage. 



4. The apparatus must be so constructed as to be absolutely 

 air-tight except where the moist air enters at the flanges, and any 

 cement used should be capable of withstanding the effects of 

 moisture, cedar-wood oil, and the temperature of a sterilizing oven 

 when it may be advisable to sterilize the contrivance before use. 



5. The cover-glass carrier is arranged so as to allow a very con- 

 siderable volume of moist air to be contained within the chamber, 

 this being necessary for the well-being of living organisms. 



6. The tablet should be small, and must permit of an oil- 

 immersion or any other objective being used up to its margin. Its 

 thickness must allow a wide-angled aplanatic substage condenser 

 to be conveniently focused through it. 



7. The wells are provided with covers to retard evaporation 

 when necessary, but they can be easily replenished with water 

 when the apparatus is in action on the stage of the Microscope. 



In conclusion, I am greatly indebted to Mr. C. Lees Curties for 

 the care he has bestowed on the construction of this little con- 

 trivance, which is, so far as I know, the only moist chamber yet 

 devised which permits of the continuous and convenient observa- 

 tion of the smallest living organisms under critical conditions with 

 the highest powers. 



