47 



one can see clearly that very different drawings would be made 

 before and after answering the questions. 



I. Cell and protoplasm (Lat., cella, room: Gr., protos, first 



plasma form). 



(a) Mount a leaf of the water weed, Philotria. Note the 



structure of the cell, the position of the green 



bodies, chloroplasts, and especially the movement 



of the protoplasm. Compare various cells. 



{b) Mount a stamen of the spiderwort, Tradescantia, 



taking care not to crush it. Note the structure 



of the stamen-hair, and especially the streams of 



protoplasm and the nucleus. 



Answer the following questions definitely but briefly: 



(i) Explain the different shapes of the cells. (2) What 



indicates that the wall is elastic? (3) Do the streams of 



protoplasm change their shape, position, or direction? 



(4) What forms the "banks" of the streams? (5) Find 



the rate of flow. (6) Does the protoplasm pass from one 



cell to the next? (7) How and why does it line the cell 



wall? (8) Explain the position and shape of the nucleus. 



(9) Does the nucleus move? If it does, explain how. 



(10) Do the streams center at it? Do they flow into it 

 or over it? (11) What fills the bulk of the cell? Draw^ 

 to scale a cell of Philotria, showing the wall and chloro- 

 plasts; draw a cell of the stamen-hair, showing wall, 

 streams of protoplasm, nucleus, etc. 



Almost all of the work is carried on in the field and green- 

 house. Lectures and books are replaced by independent labora- 

 tory (in the widest sense) work by the students. It means 

 time, patience, and real teaching power on the part of the in- 

 structors if the students are to solve for themselves the problems 

 of physiology and work out the structural adaptation to function. 

 It is also felt at the University of Minnesota that the students 

 are more interested by and in work of this type than by the 

 usual method of lectures, and text and reference books. 



