APPENDIX II 471 



is given. This is followed by useful hints on fitting up 

 apparatus. 



The carrying out of the experiments is prefaced by some 

 useful hints which I take leave to quote : " In making 

 experiments, sketch the apparatus used. Make notes of 

 the materials experimented with (name of plant or part of 

 plant, number, condition, stage of growth, etc.), the duration 

 of the experiment, date, time of day ; the external con- 

 ditions (temperature, light intensity, barometer-reading, 

 etc.) ; the precautions which seem necessary and the 

 sources of error which may spoil the results. Always make 

 ' control ' or ' check ' experiments, using the same form 

 of apparatus set up at the same time, but with one or other 

 of the conditions different, e.g. in darkness instead of light, 

 with the plants omitted, with killed instead of living plants, 

 with plants in different stages of growth. Also make 

 ' repeat ' experiments, using different plants under similar 

 conditions or the same plants at different times of year or 

 day, etc." 



Physiological work with experiments should be under- 

 taken under the guidance of an experienced teacher who 

 will explain the setting up of the apparatus, the special use 

 of each piece, and how to employ the reagents. As a 

 matter of fact some preliminary knowledge of chemistry 

 and physics is necessary before undertaking elaborate 

 physiological experiments. 



Some very simple and easily contrived experiments, that 

 can be made with improvised apparatus, are described in 

 Fritsch and Salisbury's ' Introduction to Botany,' which is 

 well illustrated with diagrams. 



3. Morphological Work. 



For general work without the microscope, dealing with 

 the external features, or gross morphology, or anatomy of 



