5 2 PLANT PHYSIOLOGY. 



Practicum " (English translation by Hillhouse, 5th ed. 1900, New York, 

 Macmillan). On obtaining Tradescantia in autumn and winter see 

 page 37. 



Owing to the nearly uniform transparency of most of its 

 essential parts, Protoplasm in a living- state shows only partially 

 its internal structure. To render this more fully visible, a 

 protoplast must be carefully killed and differentially stained ; 

 this has been done in the mounted specimens supplied. 



3. How much of the fundamental structure of Protoplasm can 

 be shown by the best-prepared dead protoplasts? 



Answer from a study of the preparations supplied, supple- 

 mented by other available data. 



If students have already studied cytology, this need be but review 

 otherwise cytological preparations should be used. 



4. What is the physical composition (i.e., the texture, density, 

 motility or rigidity, color and other optical properties) of the liv- 

 ing Protoplasm of Plants ? 



Answer by concise descriptions made during your observa- 

 tions for Exercise 2 above. 



5. What is the chemical composition of living Protoplasm? 



Direct observation and experiment upon this most impor- 

 tant subject is here impossible because of practical difficulties ; 

 answer from data gathered from lecture-notes and accessible 

 books; express in a concise paragraph. 



CORRELATED TOPICS. 

 (Important to completeness of the subject.) 



History of our knowledge of Protoplasm. 

 Present distribution of Protoplasm in space and temperature. 

 Ontogeny of Protoplasm, and the origin and meaning of death. 

 Phylogeny of Protoplasm; theories as to its origin and its 



relations with non-living matter. 

 Interpretation of the visible structure of Protoplasm, and 



theories as to its ultra-visible and ultimate structure. 

 The protoplast and its ' ' contents. ' 



