302 THE AMERICAN MONTHLY [Nov 



with au active chemical action, as if some gaseous body 

 was blown into the texture of the particles, as it increases 

 and grows in color while under observation. 



When the phenomena derived from experimental sug- 

 gestions indicated herein are fully appreciated, one is in 

 a better position to discuss the question of the vegetable 

 or protozoan characters of such phenomena. The demon- 

 stration of the phenomena postulated lierein, is of so cer- 

 tain and accurate a nature, that any microscopist, having 

 average skill, can demonstrate all of the varied phenom- 

 ena of motion, muscular energy and color changes, to 

 an audience of a hundred or more. It would be easy vrith 

 a micro-projection lantern to project the working diatom 

 in a field two feet or more in diameter, when the Navi- 

 culae would have a linear extension of fifteen or more 

 inches, and as there is a strong color contrast between 

 the diatoms, amber particles of wood and the violet hues 

 after transport contact, the phenomena would appear on 

 the illuminated projection disc, the same as in the field. 

 Then everyone according to his experience might inter- 

 pret the character values of the biological phenomena 

 thus presented and demonstrated. 



To enable one so inclined to make the verification for 

 himself with a microscope, the following suggestions, if 

 followed, produce successful results. First, secure from 

 any locality where the larger living Navicula nobilis, 

 major, and viridis are known to occur, a quantity of the 

 crude material. Water algsB, plants or muds are collect- 

 ed into a wide-mouth bottle about three and a-half inches 

 in depth and a few inches wide allowing this crude ma- 

 terial to occupy one half of the bottle, the remainder to 

 contain water. The bottle is then allowed to stand ex- 

 posed to open daylight and air. Within a day, the diatoms 

 will occupy the clear water, swimmiug free in suspension 

 and attached to the sides of the bottle more numerously. 

 On each successive night, or day as the study may per- 



