November 20, 1908] 



SCIENCE 



731 



logical discussions whicli follow. Then the 

 student is plunged at once into accounts o£ 

 variation, struggle for existence, survival of 

 the fit, and plant societies — topics which more 

 frequently form the end, instead of the begin- 

 ning, of text-books, although as here presented 

 they can readily be grasped by the beginning 

 student and may serve to enliven his interest 

 in and appreciation of what is to come. Most 

 of the botanical section is devoted to the struc- 

 ture, physiology and adaptations of flowering 

 plants, the cryptogams being dealt with in the 

 last chapter in fine print which is designed to 

 be omitted should time not be adequate for the 

 complete course. Many teachers may criti- 

 cize the limitation of the work so largely to 

 the flowering plants and the inadequate con- 

 ception it gives of the diversity and general 

 development of the vegetable kingdom. One 

 must of necessity sacrifice important subjects 

 in an elementary text, and it is quite natural 

 that the writer who stands so prominent as an 

 authority in horticulture and agriculture 

 should emphasize, perhaps unduly, those parts 

 of the subject which are more directly con- 

 cerned with these branches. Professor Bailey 

 has brought the student more closely in touch 

 with the practical aspects of botany than is 

 usually done, and this is a valuable feature of 

 his part of the book, even from the stand- 

 point of the teacher of pure science. The 

 text is clearly written and illustrated with 

 many good figures most of which are new, and 

 there are lists of questions and helpful sug- 

 gestions for worK at the close of the various 

 chapters. 



The zoological part of the work sufFers con- 

 siderably in comparison with the preceding. 

 Errors are numerous and frequently serious, 

 while there are many more statements which 

 are misleading or inadequate. Space will not 

 permit us to point these out in detail, but the 

 following will serve to indicate sufiiciently, I 

 think, the general character of the work. 

 After describing Amwlia and Paramoecium we 

 have the statement : " Other classes of Proto- 

 zoans are the infusorians, which have many 

 waving cilia (Fig. 17) or one whip-like flagel- 

 lum (Fig. 18), and the foraminifers which 

 possess a calcareous shell pierced with holes 



(Fig. 19)." In the first place the infusorians- 

 do not, as the statement implies, form another 

 class in addition to that represented by Para- 

 ■mcecium, they do not in most recent systems 

 of classification and certainly should not in- 

 clude the fiagellata, many of which have two 

 or more fiagella instead of one; nor are the 

 foraminifera ranked as another class distinct 

 from the rhizopods to which Amceha belongs, 

 but as a subordinate division of the same 

 group ; they do not all possess a calcareous 

 shell; in large numbers of species the shell 

 is not pierced with holes ; and the figure which 

 is supposed to represent one of them is a 

 picture of a radiolarian! 



In Fig. 23 what are called the eggs of the 

 fresh-water sponge are doubtless the gem- 

 mules. After informing us that in sponges 

 " the ciliated cells and the reproductive cells 

 are the only specialized cells," and that " slow- 

 growing sponges grow more at the top and 

 form tall, simple, tubular or vase-like animals. 

 Fast-growing sponges grow on all sides at 

 once and form a complicated system of canals, 

 pores, and oscula," we are given an illumina- 

 ting account of how sponges may have arisen 

 from unicellular ancestors. 



Several one-celled animals happened to live side 

 by side; each possessed a thread-like flagellum or 

 whip-lash for striking the water. By lashing the 

 water they caused a stronger current than proto- 

 zoans living singly could cause. Thus they ob- 

 tained more food and multiplied more rapidly 

 than those living alone. The habit of working to- 

 gether left its impress on the cells and was trans- 

 mitted by inheritance. Cell joined to cell formed 

 a ring; ring joined to ring formed a tube which 

 was still more effective than a ring in lashing the 

 water into a current and bringing fresh food 

 (particles of dead plants and animals) and oxygen. 



Comments are superfluous. 



In the description of the nettling cells of 

 hydra the fact is announced that after their 

 discharge " when the pressure is withdrawn the 

 thread goes back as the finger of a glove may 

 be turned back into the glove by turning the 

 finger outside in." In the same chapter oc- 

 curs also the misstatement that " the hydra is 

 the only fresh-water representative " of the 

 " branch polyps (sometimes called Ooelen- 



