1906] Principles of Botany 231 



with exposition of function. The separation or absolute divorce of 

 these kindred and mutually explanatory topics in many text-books 

 and also in the class room has always been deplorable, but there are 

 signs that in the near future no botanical teaching, even of the simplest 

 kind will be considered acceptable that does not treat the plant as a 

 living thing, and try to show how its organs perform their work. 

 Teachers will find much that is suggestive also, and much to draw 

 them and their classes out of doors in the concluding chapters on plant 

 formations, plant geography, and kindred subjects. 



Mr. Bergen's definitions might occasionally be bettered. For 

 instance, the opening sentence of chapter one speaks in traditional 

 terms of the seed as "reproducing the kind of plant which bore it," 

 thus suggesting at the outset a meaning for the word reproduce which 

 has to give way later to a much more exact conception of reproduction 

 as distinguished from mere growth. In just this point a text-book 

 ought not to err. So much depends on the exact use of terms, that a 

 teacher must weigh well every word in order not to plant wrong ideas 

 which, like weeds, go on to flourish, and have to be uprooted later. 

 No teacher enjoys weeding an intellectual garden, and he should be 

 especially careful himself to sow only pure seed. Another instance of 

 the same kind is the first definition of the term cell (p. 9) as a "micro- 

 scopic compartment," replaced later (p. 35) by a second definition — 

 from the biological standpoint — as "a unit of protoplasm, called a 

 protoplast" — and again by a third (p. 158, by Dr. Davis) as "a small 

 mass of protoplasm containing a nucleus.' Definitions two and three 

 are italicized in the text. 



Of Dr. Davis's chapters almost everything to be said must also be 

 in commendation. His is the harder subject as a matter of presenta- 

 tion, for it is much more complicated and unfamiliar in detail, and 

 necessarily for a beginner bristles with technicalities. The descrip- 

 tive portion, rich in material and clear in wording, should be easily 

 comprehensible to students intelligent enough to use a compound 

 microscope. The philosophical portion will doubtless be over the 

 heads of all but mature students. It is certainly necessary nowadays 

 to interpret the results of studies in comparative morphology from the 

 evolutionary point of view, but it is none the less difficult, for we are 

 led at once into a region of uncertainty and speculation. In this 

 region a beginner will surely feel the ground insecure, and will have 

 to be forgiven for failure of comprehension, or for that skepticism 



