578 



NA TURE 



\_April 2 1, 1887 



mycetes are wholly asexual forms, their so-called fruit 

 repiesenting a complex gonidiophore. 



Leaving the Thallophytes, many signs of advance will 

 be found in the description of the Muscine^e. Attention 

 may especially be called to the very clear account now 

 given of the embryology both of the Liverworts and of 

 the true Mosses. In a future edition a fuller account of 

 the vegetative anatomy of the latter class may perhaps 

 be looked for. 



In the group of the Vascular Cryptogams the changes 

 have been very numerous. Goebel's view of the essential 

 distinction between the forms in which the sporangium 

 arises from a single cell, and those in which a whole 

 group of cells takes part in its formation, gives the clue 

 to the arrangement here followed. Indeed, there is no 

 part of the book in which the author's own researches 

 have given rise to more important results. The whole 

 subject of the development of the sporangia, both among 

 vascular cryptogams and flowering plants, is one which 

 Goebel has especially made his own. 



As regards other points, we may mention that the 

 important subject of apogamy in Ferns is treated at length 

 in the text, while the converse phenomenon of apospory, 

 more recently investigated by Prof. Bower, is dealt 

 with in an editorial note. The embryology of the 

 whole group is treated much more completely than 

 before, and illustrated by new figures. The brilliant 

 discoveries of Treub in the Lycopodiaceas are shortly 

 recorded in a note, but his most recent work did not 

 appear in time to be noticed. 



Going on to the Gymnosperms, we find that the re- 

 searches of Treub have here led to important advances 

 in our knowledge of the Cycadei-e. The Coniferse are 

 treated very fully, and here it is more especially to thef 

 labours of Strasburger that the most important pro- 

 gress is due. To him are to be attributed most of 

 the recent discoveries on the development of the macro- 

 sporangium and of the prothallus and embryo. It 

 need scarcely be pointed out that these results, in con- 

 junction with the investigations of the author himself, have 

 demonstrated in every detail the homologies between 

 Gymnosperms and Pteridophyta long ago detected by 

 the genius of Hofmeister. 



Before leaving the Coniferse, attention must be called 

 to an eiTor which has, curiously enough, survived through 

 several editions of Sachs's " Text-book," and through 

 both the German and the English versions of the present 

 work. At the middle of p. 337 it is stated that in 

 Juniperus the lowest of the three cells derived from the 

 oospore divides into four cells, each of which gives rise 

 to a rudimentary embryo, so that four rudimentary 

 embryos proceed from one archegonium. At the bottom 

 of the same page we find the following sentence : "But 

 Picea vi/lgans agrees with Juniperus, inasmuch as the 

 lowest of the three primary cells of the suspensor does 

 not divide, but forms only one rudiment." Of these two 

 contradictory statements the former is, of course, the 

 correct one ; in the sentence last quoted. Thuja should 

 be read for Juniperus. 



As regards the Angiosperms, the mos': considerable 

 changes introduced relate to the development of the 

 stamen on the one hand, and of the ovule and embryo- 

 sac on the other. In the former case it is especially the 



work of Warming, in the latter that of Strasburger, to 

 which our present knowledge of the facts is due. The 

 treatment of all these subjects by the author of this book 

 is singularly clear. The student will see how the homo- 

 logies, which were so evident in the case of the Gymno- 

 sperms, can also be traced here up to a certain point, 

 while he will also see exactly where our knowledge is still 

 deficient. 



The improved account of the embryology of Angio- 

 sperms may also be noticed, especially the interesting sum- 

 mary of Strasburger's investigations on polyembryony. 



As regards the translation, both Mr. Garnsey and Prof. 

 Balfour may be warmly congratulated on their success. 

 Here and there a slight want of clearness may perhaps be 

 noticed, but this is very rare, and scarcely any errors have 

 been detected. One on p. 17 may, however, be pointed 

 out. It is there stated that in the Myxomycetes "a 

 Plasmodium moves away from illuminated spots ; if a 

 stronger light is thrown directly upon these spots, a num- 

 ber of Plasmodia collect in them." This does not express 

 the fact as stated in the original, which is that, if the Plas- 

 modia be directly exposed to strong light, they form larger 

 conglomerations. Again, at the top of p. 97, the phrase 

 " /V/j- /7r/<7 " should scarcely have been translated "into 

 the air," in speaking of a submerged aquatic plant. 



The explanation of terms at the end of the book will 

 be of the greatest possible value not only to students but 

 to botanists. We may hope that it will materially con- 

 tribute to introduce order into the chaos of our termino- 

 logy. We are glad to see the good old term spermato- 

 0[)/rf replacing the inaccurate antlierozoid, and we could 

 wish that ovum could constantly be used for oosphere. 

 Where clear homologies with the animal kingdom can be 

 traced, it seems a distinct loss to ignore them. 



On the other hand, we cannot feel satisfied with the 

 word " sporophyte '' for the asexual generation in the 

 higher plants. "Sporophyte" is the correlative of 

 " spermaphyte," and has actually been used by Luerssen 

 and others in the sense of a Cryptogam, as distinguished 

 from the seed-bearing Phanerogam. We should have 

 thought that the older terms "sporophore" and 

 " oophore " would answer every purpose. 



In conclusion, we can only say that the appearance of 

 this book marks the most important addition to our 

 morphological literature since 1875. D. H. S. 



MINERAL PHYSIOLOGY AND 

 PHYSIOGRAPHY 

 Mineral Physiology and Physiography. A Second Series 

 of Chemical and Geological Essays, with a General 

 Introduction. By Thomas Steny Hunt, M.A., LL.D. 

 Pp. 6S8. (Boston: Samuel E. Cassino, 1886.) 



THIS work, as its sub-title implies, is a continuation 

 of the series of essays first published by Dr. Sterry 

 Hunt in 1874, of which a second and revised edition 

 appeared in 187S. The essays which make up the pre- 

 sent volume have with one exception, that on " The 

 Genetic History of Crj'Stalline Rocks," already appeared 

 in various scientific journals. 



The principal title of the work is explained and justi- 

 fied by its author in the two first essays. Dr. Sterry 

 Hunt advocates a return to the older and wider meaning 

 of the term " physiology " as it was employed two 



