APPENDIX 523 



Eggs of pond snails (Physa, etc.) for study 37 may 

 usually be obtained in late winter by bringing the snails in 

 from the ponds, where they may easily be picked from bot- 

 tom trash or from floating boards, and placing them in bowls 

 of clean water. Provide them with bits of cress or cabbage 

 or other fresh leaves to eat. Within twenty-four hours the 

 elongated and transparent egg masses will Ijegin to appear, 

 sticking to the sides of the vessel. The vessel should be 

 kept clean, for silt adhering to the gelatinous covering will 

 hinder observation. The egg masses may be divided into 

 small parts and distributed for study. 



Planarians for study 42 may be picked from stones lifted 

 out of a clean creek bed or out of the surf on the shore of a 

 lake, or often from the trash in a spring pool. 



Carriers for handling the numerous plants in thumb pots 

 needed in study 38 may be made by partly filling any shal- 

 low tray with wet sand, and soldering stretched poultry 

 netting of suitable mesh across the top. Set the pots in the 

 sand. The wires will prevent their toppling over, and they 

 may easily be carried back and forth as may be necessary 

 between laboratory and greenhouse (or lighted window). 



Grafting wax (for study 44) : 

 Rendered tallow i part. 

 Beeswax 2 parts. 

 Resin 4 parts. 



Melt together with heat; pour into a pail of cold water; 

 pull (like taffy) until light colored; and put away for use. 

 The heat of the hands will soften it sufficiently for applica- 

 tion. 



Grafting is to be attempted in spring just before growth 

 starts. Cions are better kept over winter in a cool cellar 

 in moist (not wet) sand, but can be cut, if still dormant for 

 immediate use. Seedlings to be grafted can readily be 

 grown in a garden, but large trees are often available, and 

 wild crab apples, in the woods. The operation of bud 



