Nov. lo, 1887] 



NATURE 



29 



graph is an admirable device for fixing the student's 

 attention on one thing at a time, and is aided by the 

 numbering and lettering of the paragraphs. The division 

 into sections dealing with groups of characters, leading 

 the student on from the more obvious features to those 

 less easily investigated, also stamps the work as that of 

 experienced teachers, and is eminently English. 



The only part of the plan to which objection is likely 

 to be raised by teachers is what may perhaps be termed 

 the reversal of the order of the types. We are ourselves 

 inclined to the opinion that it would have been better to 

 begin with the more lowly organized types, and work 

 upwards to those in which the anatomy and histology 

 become more complex. There is much to be said in 

 favour of the method adopted, but we think that the fol- 

 lowing two objections to it alone outweigh all we have 

 heard in its favour. 



(i) The types are obviously selected as illustrating the 

 chief structural peculiarities of plants, and it might be 

 better to at least indicate the relations of these structures 

 in an order more in accordance with their probable 

 development in the vegetable kingdom. 



(2) The plan of teaching which marks the book is the 

 educational one, i.e. the observer is led on from simple to 

 less simple ideas. This is only carried out consistently, 

 however, within the individual sections of the book : why 

 should it not be followed throughout the work ? 



Of course the objection may be anticipated that the 

 sections really lead the student on from the macroscopic 

 to the microscopic characters, and that Algae and Fungi, 

 for instance, are less easy to investigate, and therefore 

 come last, because they involve the use of the higher 

 powers of the microscope so much. We do not admit that 

 this latter is a difficulty, however, and in reply would 

 simply propose for psychological study the mental 

 attitude of a tyro struggling with his first transverse 

 section of a sunflower-stem. The cutting, preparation, 

 mounting, and finally the involved pattern of cell-walls 

 which he has to unravel, at once plunge him into diffi- 

 culties at least as great as those met with on the threshold 

 of the study of the Algae. Moreover, there is evidence in 

 the work that the student is supposed to be acquainted 

 with the use of the microscope, such as would be obtained 

 from a proper course of elementary biology. 



Of course, however, it is always open to a teacher to 

 reverse the order of the types in the book ; and it only 

 remains for us to say a few words regarding some of 

 those employed in the second volume. Polytrichiim is 

 selected as the chief type of the mosses, and we think 

 Dr. Bower has done well to illustrate the details of 

 structure by this complex form, surmounting the difficulty 

 presented by its peculiar sporogonium by a comparative 

 study of that of Ftmaria — itself an excellent type. We 

 are glad to see M archantia treated in detail. It is, of 

 course, an out-of-the-way form, and is peculiar even in its 

 own group, but it is an instructive plant, and one that has 

 earned areputation from the physiological lessons it teaches 

 us. Polysiphonia serves as the chief type of the red sea- 

 weeds, and although it has many peculiarities, it has the 

 advantage of being common : the structures of several other 

 Florideae are shortly compared with that of Polysiphonia. 

 Fticus serratus forms an excellent type for the study of 

 the brown sea-weeds, and as it is easily obtained, it 



should be employed in every laboratory course: the 

 details of the actual process of fertilization still offer an 

 interesting problem to any intelligent student, but the 

 chief stages in the process are not difficult to observe. 



Passing to the green Algae, CEdogoniwn seems to us a 

 type well worth thorough study in the laboratory ; it is 

 by no means uncommon, and an effort should be made to 

 introduce a definite species of the larger forms as a type. 

 Short studies of Coleochate and of Ulothrix are also 

 given. Vaucheria sessilis is offered as an example of the 

 Siphoneae, and we are glad to see it brought well into the 

 foreground; this again is a plant of increasing import- 

 ance as an instructive plant. Most of the details of the 

 process of fertilization in this Alga offer less difficulties 

 than is commonly supposed, and students should be 

 encouraged to spend some time on their study. A short 

 resume' of the main points is given. No doubt the 

 presence of Protococcus or Hcematococcus in schedules 

 of elementary biology explains its omission from the 

 present work : Pleurococcus and Volvox are given, 

 however, and they illustrate several points of importance. 

 In spite of — or perhaps on account of — its very marked 

 peculiarities, we look upon Spirogyra as one of the most 

 instructive types that the student can examine, and 

 Dr. Bower has done well to give it a prominent position. 

 It deserves more attention, however, and we would 

 strongly urge an exhaustive treatment of its life-history, 

 germination, and some of the physiological lessons it 

 teaches. 



Passing over less important forms, we may now say a 

 few words respecting the Fungi given as types lor study. 

 The first section is devoted to Agaricus, and a capital 

 study of the structure and histology of the common 

 mushroom is given. Then follows an equally good 

 account of the vEcidiomycetes. Of Ascomycetes, we 

 have Peziza, Parmelia, Claviceps, and Eurotiutn, as types 

 of the chief great groups. A word as to Peziza. It is 

 an excellent type, and certain forms can be cultivated, 

 and we hope that in a second edition the author will 

 see his way to introducing a fuller account of some one 

 species. At the same time we are not sure that Ascobolus 

 is not a better form for the present purpose : it can be easily 

 cultivated, and its small size is an advantage, since per- 

 fect sections can be obtained across the whole plant. 

 Another excellent type is also introduced in the study 

 of the Peronosporeae. English students are only now 

 becoming aware of the theoretical importance of this 

 group, and we are very glad to see Dr. Bower's section 

 on Pythiuin de Baryanum : it cannot be too well under- 

 stood that Pythium is one of the few parasitic Fungi 

 which may be easily cultivated and followed through all 

 its phases of development in the laboratory. For our 

 own part, we regard it as the best of all Fungi for study, 

 and its life-history and simple structure ought to be 

 thoroughly investigated in every botanical course. It has 

 the additional advantage of being also a saprophyte, 

 and can be cultivated on dead organisms. The Mucorineae 

 are exemplified by Mucor and Sporodinia. No type of 

 the Ustilagineae is given. 



Enough has been said to show that the volume pre- 

 tends to no more than it can fairly claim, and we regard 

 it with confidence as a praiseworthy and successful 

 attempt to record for the benefit of a wide class of 



