1028 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Tbo whole of the lower part of the Microscope, with the object, is 

 inclosed in a metal box, the four walls and bottom of which are double. 

 The two sides are hinged on the bottom so that they can be turned down 

 to facilitate the arrangement of the object in the first instance. These 

 are filled with asbestos ; the other two and the bottom being filled with 

 water. The walls and top are covered with felt. A lamp beneath heats 

 the water, which warms the air in the box. A thermometer passing into 

 one of the walls shows the temperature of the water, and a second one 

 passing through the top into the interior shows that of the inclosed air 

 and the object. If it is desired to move the object during observation, 

 an oval opening in one of the sides (closed by the cover shown on the 

 ground between the two figs.) enables the hand to be introduced, and 

 so saves the lowering of temperature which would be likely to arise if 

 the whole side were let down. The inner surfaces of the walls are, in 

 use, lined with several layers of wet blotting-paper. 



Dr. Nuttall considers that the apparatus has great advantages over 

 an ordinary warm stage, as the temperature can be maintained to fractions 

 of a degree for a long time, and the thermometer shows accurately the 

 temperature of the object. 



Modification of Pagan's "Growing Slide."* — Mr. Selmar Schon- 

 land, referring to the arrangement designed by the Rev. A. Pagan for 

 growing on microscopical slides small organisms, such as rotifers, algae, 

 &c., which live in water and require a frequent change of the medium, 

 says that the results obtained with it were very remarkable. In the 

 original design, however, the slide had always to bo removed from the 

 Microscope and kept on a specially constructed stage ; and although in 

 many cases this is of no importance, yet occasionally it is a very great 

 drawback. The author has, therefore, devised an arrangement which 



Fig. 174. 



allows of the slide being kept constantly on the stage of the Microscope, 

 and thus of the continuous observation of the same individual for weeks, 

 and even, under certain conditions, for an indefinite period. The 

 arrangement is represented in fig. ITl. 



The slide A has the ordinary form, but is made slightly longer than 



* Ann. of Bot., ii. (1888) pp. 227-31 (2 figs.). 



