A MICROSCOPE-STAGE INCUBATOR 



J. THOS. PATTERSON. 



The desirability of studying the living egg in connection with 

 any embryological investigation has long been recognized, and 

 the excellent -results obtained from such studies have demon- 

 strated repeatedly the advisability of putting forth every effort to 

 overcome any obstacles that might stand in the way of such 

 observations. Hitherto direct observations on the developing 

 bird's egg have not been possible, for such a study is beset with 

 many difficulties, chief among which is that of incubation. In 

 an endeavor to overcome this difficulty I have been led to devise 

 the following microscope-stage incubator, which not only fulfills 

 my purpose admirably, but also gives promise of being useful in 

 the study of other biological problems, especially those in which 

 it is necessary to maintain a constant temperature while making 

 direct observations on the living organism. 



The photograph (Fig. i) shows the apparatus connected up 

 and ready for use with a compound microscope although a 

 binocular can be used as readily. The incubator consists of a 

 galvanized-iron tank, a portion of which fits over and in front of 

 the microscope stage. Just above the center of the stage a hole 

 is cut in the lid of the tank and in this is placed a covered dish, 

 or egg-cell e. This arrangement allows one to study the egg 

 readily and at the same time to make camera drawings of the 

 object under observation. 



The water in the incubator is heated by a sixteen-candle power 

 incandescent lamp / connected with a thermoregulator r, which 

 is patterned after the glycerin type described by Mast (Science 

 for October 25, 1907). The bulb or immersed part of the 

 regulator is bent at right angles to the upper portions, in such a 

 way that it extends towards the microscope stage, reaching 

 almost as far as the egg-cell. This arrangement not only places 

 the bulb directly in the path of the current which flows from the 



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