18 STUDIES IN PHYSIOLOGY. 



PRACTICAL EXERCISES IN VEGETABLE 

 PHYSIOLOGY. 



This course of cxpei'iineuts in Vegetable Phj-siology is divided 

 into two parts : the first series comprises a few exercises wliicli 

 can be undertaken bj- any one liaving only the simplest appli- 

 ances ; the second requires more complicated apparatus. The 

 first series, if faithfully and intelligently followed, should place 

 the student in possession of the leading facts regarding the prin- 

 cipal activities of the plant ; while the second series should ac- 

 quaint him with the chief methods employed for the investigation 

 of the special offices of the organs of the plant, and fix the 

 principal results in his mind. It should, however, be frankly 

 stated that for the proper and satisfactorj' performance of the 

 experiments detailed in this second or special series the student 

 should first become familiar with the ordinary methods of chemi- 

 cal and ph^'sical manipulation, and have at command the funda- 

 mental principles of chemistry and of phj'sics. 



FIRST SEEIES. 



In this series are discussed experimentally the following car- 

 dinal topics : (1) The behavior of protoplasm in a living cell; 

 (2) The gain in substance by assimilation and the loss of sub- 

 stance by growth ; (3) The chief conditions under which plants 

 assimilate ; (4) The dependence of the principal activities of the 

 plant upon certain external conditions. 



The experiments can be conducted with the following ap- 

 pliances : — 



1. A small balance with weights ranging from twenty grams 

 to one centigram. If a balance is not procurable, ordinary hand- 

 scales with horn or brass pans will answer verj- well. 



2. A water-bath, or in place of it a small porcelain-lined 

 kettle of one or two pints capacity, fitting into a larger iron 

 kettle. Water placed in the larger kettle prevents the inner one 

 from being heated above the boiling-point of water. 



3. Haifa dozen test-tube's. 



4. Three or four pieces of glass tubing, six inches long. 



5. A small camel's-hair pencil, and India ink. 



6. Pieces of colored glass or colored gelatin (red, yellow, 

 green, blue, violet), six inches square or larger. 



