fi8 THE STUDY OF LIVING CELLS. 



3. The thin colorless cell wall surrounding a central granular 

 mass of protoplasm. 



4. Chlorophyll tjnnt"l<'>* distributed through the protoplasm. 

 These are the centers of the vital processes in the cell, and in sun- 

 light by the decomposition of plant food form starch, protoplasm, 

 etc. 



5. The nucleus. 



Stain the preparation with iodine and observe the effect on the 

 wall, and protoplasmic contents. (See p. 7.) 



Prepare another slide and stain with a fresh solution of 

 chlor-iodide of zinc, to observe the effect of the thin cellulose, cell 

 wall. By pressing on the cover glass, the cell contents can be 

 forced out and the cell wall be made more visible. (P. 11.) 



Examine several specimens to observe the various stages in 

 the division of the plants into groups of individuals. 



Many of the small plants will be seen moving about through 

 the water. This is due to the presence of cilia which, by their 

 rapid movements, propel the individual. Parker's Biology, p. 23 ; 

 Strasburger, p. 214 ; Vines' Text Book, p. 236 ; Campbell's Struc- 

 tural Botany, p. 22 ; Bibliography of the Literature on the 

 Plant Cell, by Dr. A. Ziramermanu ; Botanisches Centralblatt, 

 Beihefte, 1894. 



Further Illustration: POLLEN-GRAINS and their MOTHER-CELLS, 

 from Begonia sp . 



PREPARATION FIRST: For the MOTHER-CELLS of POLLEN. Lay out 

 a perfectly clean glass slide and cover-glass, placing a few drops of 

 distilled water on the former. Select a young staminate flowe? lm<1 

 (less than half grown). Moisten the razor edge and make thin sec- 

 tions across the upper part of the flower buds, and the tips of the 

 contained anthers. From these sections select the thinnest, espe- 

 cially those of the anthers and remove by means of a camel's hair 

 brush to the slide. Examine these sections with a tripod lens or a 

 dissecting microscope, removing the thicker anther sections and 

 fragments of the perianth. Cover the sections with the cover-glass. 

 The latter should be taken up with the forceps, one edge placed in 

 the water, and the glass lowered, not too suddenly, but so as to 

 allow the water to run along its lower surface without enclosing 

 any air bubbles. Examine first with the low power objective (^ in.), 



