MICROSCOPIC MOTION PHOTOGRAPHY 111 



Each microscopic picture made is an engineering 

 problem and the difficulties to overcome are in their 

 way as great as building a bridge across a river. 

 Many subjects require a great deal of time, first to 

 gain a knowledge of their habits. Spirogyra for ex- 

 ample; it is easy to take all sorts of pictures of it, 

 some of them showing some action, but action that 

 few people have seen, like the act of conjugation, is 

 the most thrilling step in its life story, and it means 

 hours of patient watching. 



I am planning to add to my equipment one of the 

 new automatic reflecting arc-lights, and a high speed 

 camera, to enable me to work on bacteria. My pres- 

 ent cameras will not carry film faster than thirty 

 frames a second, without too much vibration, and 

 my lights, with dark field illumination, are not 

 strong enough to give full exposure at higher speeds 

 which are necessary, and as I mentioned before, a 

 microscopic unit is never complete each subject re- 

 quires special methods and apparatus, making it 

 doubly expensive. 



