68 BOOKS AND CURRENT LITERATURE 



On pages 55 and 67 the teaching is that breathing and respiration are 

 synonymous, that plants "breathe," and that the taking in of oxygen and 

 giving out of carbon dioxide together constitute respiration. Doubtless 

 there is plenty of weighty precedent for this view, but it is very unfor- 

 tunate nevertheless, and ought no longer to be perpetuated. Our under- 

 standing of metabolic processes has now reached a stage when we recog- 

 nize respiration as, in essence, a cell-process in both plants and animals, 

 accompanied (usually but not always) by the exchange of gases just 

 referred to. It is this exchange of gases to which, in animals, the term 

 breathing should be restricted; in plants, and in some animals, e.g., 

 the earthworm, it is not breathing, but simply the physical process of 

 diffusion. The reviewer is firmly of the opinion that this terminology 

 is not only more nearly adequate to our present state of knowledge of 

 these processes, but is pedagogically desirable as conducing to clearer 

 thinking. 



Greater uniformity is desirable in presenting the concept "cell." 

 On pages 69, 70 and 71, the cell is presented as a cavity "containing 

 living matter," while on pages 41 and 79, it is described as "composed 

 of cell-substance." The two conflicting views occur together on pages 



69 and 71. Also on page 71 it is stated that the slippery-elm bark owes 

 its peculiar property to the cambium between the bark and wood, 

 instead of to the mucilage of the inner bark. 



From paragraph 77 (p. 80) the pupil will probably get the idea that 

 dorsal and upper, ventral and lower are synonymous. This is especially 

 misleading with reference to plants; the normally lower surface of the 

 expanded foliage leaf, for example, is the morphologically dorsal surface. 

 The flounder is an easy animal exception for a botanist to think of. On 

 page 90 it is stated that the osmoscope experiment demonstrates that the 

 molasses employed "attracts" the water, and again on page 92, the attrac- 

 tion hypothesis of osmosis is the only one referred to. The assertion 

 at the top of page 101, that "most plants without chlorophyll are sapro- 

 phytes," is doubtless open to question, if not certainly incorrect; while 

 a few lines below (^[99) parasitism is overlooked in the statement that 

 non-chlorophyll bearing plants must absorb their carbohydrate food 

 from the "decaying" bodies of other plants or animals. 



We read on page 109 that "no one has yet found any other substance 

 except starch with which iodine solution gives this peculiar blue color 

 seen in starch." As plant physiologists well know, not only are there 

 other substances besides starch that will give the blue reaction with iodine 

 but some starches will not give it. 



