60 THE MICROSCOPE. Apr., 



them Diatoms, which is the English of the scientific 

 Latin Diatomacese. So they may call Bacillariacese 

 Bacills. But Diatoms are the siliceous shells, or loricse 

 of the perfect organism. The organism itself is a mass 

 of protoplasm which secretes within itself the Diatom, 

 just as shells are the loricse of Mollusca and bones of 

 man, so that when observing Diatoms we are not studying 

 Bacillariacese. To study them requires time and patience. 

 We can observe Diatoms and mount them to show them 

 but that is very different from studying them. To study 

 them, the observer must be a microscopist of no mean 

 character and know biology, the science of plants and 

 animals. He should be a physicist besides, and this 

 requires time and jjatience. An observer may see the 

 diatoms when looking at about one hundred slides but 

 the student of the Bacillariacese has to spend many hours 

 of patient toil to work out even the outline of one Cosci- 

 nodiscus. Pleurosigma angulata requires many obser- 

 vations on specimens from various localities. 



The Bacillariacese are not animals nor vegetables but 

 possess characters that have induced Hseckel and other 

 observers to rank them along with other organisms tem- 

 porarily in a kingdom by themselves, in the Protista. 

 But kingdoms are only transitional and they but items of 

 the lowest organisms. Low because they carry on their 

 life in a simple manner. And because they are so 

 simple they are not affected by what we call evolution. 

 Those that first existed in the Laurentian are the same 

 as grow now. Epithemia turgida of the Silurian age is 

 Epithemia turgida of the recent. 



Students must not forget that Bacillariacese is but a 

 name for organisms which are seemingly simple in char- 

 acter and bye-and-bye we may have to record complex 

 things that they do and mighty work that they accom- 

 plish. They are simple when viewed by present knowl- 

 edge, but they are mighty when viewed by the results. 



