STRUCTURE AND PROPERTIES OF PROTOPLASM 63 



lability of the proteid constituents, and the probable relation of 

 that lability to the phenomena 0} lije. Certain related matters, 

 such as the chemical stages in the formation of Protoplasm, 

 and its mode of releasing energy for the performance of work, 

 can be treated more profitably later under Conversion and Res- 

 piration. 



LITERATURE. Upon this subject knowledge has not advanced 

 materially in recent years, and little has been added to the work of 

 REINKE and RODEWALD in 1881-1883, which may be traced through 

 PFEFFER'S " Physiology," and the chemical results of which are given in 

 brief in JOST'S " Lectures " and in GOODALE'S " Vegetable Physiology." 

 The subject is treated fully and technically in CZAPEK'S recent exhaus- 

 tive work, " Biochemie der Pflanzen " (Jena, Fischer, 1905, two vols.). 

 On the relations of chemical composition and lability to vital activity, 

 there is a short book by LOEW, " The Energy of Living Protoplasm " 

 (London, Kegan Paul, 1896), and there is a good synoptical article by 

 the same author in Science, II, 1900, 930. Of most importance on this 

 subject, however, is LOEB'S book, " The Dynamics of Living Matter " 

 (New York, Columbia University, 1906), to which should be added 

 his article on the " Chemical Character of the Process of Fertilization" 

 in Science, 26, 1907, 425. 



SECTION 3. THE VITAL STRUCTURE AND PROPER- 

 TIES OF PROTOPLASM. 



Living Protoplasm, as already noted, is unlike all other known 

 substances in possessing two sets of properties or qualities, a 

 physical set already studied and a vital set here to be considered. 

 It is indubitable that in their ultimate nature the two are not 

 different in kind, and the vital will sometime be found analyzable 

 into the physical. Nevertheless the vital properties are not at 

 present resolvable into anything simpler, nor are they known 

 to exist outside of the living organism, for which reasons it is 

 logical as well as convenient to consider them apart. The stu- 

 dent will gain a knowledge of these properties during the work 

 of the present course, and it will here suffice, in order to complete 

 the present topic, merely to name them. They are variously 

 classifiable, but may be designated thus: metabolism, growth, 

 division, motility, responsiveness to stimuli, regulation. A fea- 



