SUPPLEMENT 



will be quick to compare them with familiar objects. A class of little 

 folks with whom I once experimented likened the cells to links of 

 sausage, and the homely comparison showed that they were thinking 

 of the cell as some substance enclosed in a sac ; a truer conception 

 than the botanists who named the cell possessed, for the early 

 botanists, using sections of higher plants, gave their attention only 

 to the cell wall and quite missed the fact that the wall is to the cell 

 only what its shell is to a snail or lobster. 



Children should be allowed to find out for themselves that chloro- 

 phyll is dissolved by alcohol, and that the jelly-like substance and 

 the granules still remain. As a matter of fact, chlorophyll is confined 

 to small protoplasmic bodies called chloroplasts, but in the water nets 

 these chloroplasts are so closely packed ' against the cell walls that 

 the cell contents seem uniformly colored. There are other details of 

 cell structure that it would not be wise to impose upon children. For 

 instance, the protoplasm in mature cells lines the walls but does not 

 fill the entire cell cavity, there being much water or cell sap ; in each 

 cell some of the protoplasm is differentiated into nuclei that take part 

 in cell division ; the starch stores are collected about little glistening 

 bodies called pyrenoids, etc. In the Popular Science Monthly, Sep- 

 tember, 1896, the teacher will find a summary of what is at present 

 known about the cell and the division of labor among its parts. 

 Kerner, in the first chapter of his Natural History of Plants, gives 

 a vivid conception of the cell. He says : " It is not a mere phrase, 

 but a literal fact, that the protoplasts build their abodes themselves, 

 divide and adapt their interiors according to their requirements, store 

 up necessary supplies within them, and most important of all, provide 

 the wherewithal needful for nutrition, for maintenance and for 

 reproduction." 



The bubbles of gas given off by the plants in the sunlight can be 

 easily tested by means of a simple apparatus. Some water net is put 

 under a glass funnel in a glass jar of water, and a test tube filled with 

 water is inverted over the end of a funnel. After the apparatus has 

 been kept in the sunlight two or three days, the water in the top of 

 the tube will be replaced by enough oxygen to be easily tested. The 

 teacher has only to take the tube from the jar and invert it, keeping 

 the open end covered until an assistant has lighted a match or a 

 splinter and blown out the flame after an instant ; when the glowing 

 wood is inserted in the gas, as the cover is removed, the oxygen cau c es 

 it to burst into flame. It will seem quite credible to the children that 

 this gas which rekindles the flame is the life-sustaining portion of the 

 air. In the first chapter of NeweWs Lessons in Botany several 



