294 THE AMERICAN MONTHLY [Sept 



worm-wood smooth, elliptical, and yellowish, some grains 

 resembling- a three-leaved clover. Mr. Pfister's notes do 

 not profess to be exhaustive, but the}^ are sug-g-estive,and 

 are worth following up. He mounted the pollen in sweet- 

 almond oil, without previous preparation, and finished 

 with a ring- of gold size. 



MICROSCOPICAL APPARATUS. 



The Micromotoscope. — Dr. Robert L.Watkins says that 

 living microscopic objects may be presented on a screen 

 with an instrument which he calls a micromotoscope. 

 After overcoming- several obstacles he found it possible to 

 do this directly by the use of a special arc lig-ht, but the 

 one g-reat obstacle — heat — dried the specimens sopromptly 

 that the living- objects were killed and the method had to 

 be abandoned. The appearance of the vitascope, however, 

 sug-g-ested the possibility of applying- some such method 

 to the studies he was pursuing-. This proved perfectly 

 successful. By means of this instrument he discovered 

 that the active motion of living- microscopic objects could 

 readily be photog-raphed. By using- from fifty to a hun- 

 dred and fifty feet of the vitascopic film, and taking a series 

 of impressions in sufficiently rapid succession, he has been 

 able to secure pictures which when passed throug-h a lan- 

 tern at the same rate of speed will present on a screen all 

 the motions of the objects photog-raphed, and can be wit- 

 nessed by an audience of any size. 



Dr. Watkins thinks that the value of this discovery can 

 not be overestimated, not only for use in studying- the vital 

 processes of microscopic life, but also as a method of 

 teaching students and the public. In his investigations, 

 this method has been applied more especially to the study 

 of blood-corpuscles, and he states that the active motion 

 of the leucocyte can thus be readily reproduced. It may 

 be seen to stretch out its fingerlike prolongations and then 

 retract them. The nucleus may also be seen to vary its 

 shape, to split up into two or more, and sometimes the cell 

 itself to divide into many parts. 



