NOTICES OF BOOKS. xm 



opinion that in " Hymenomycetal Fungi really parasitic species are almost if not wholly 

 unknown ". 



In the introduction to the section on Classification, a sketch of the Brefeldian system is 

 given, though it is not adhered to by Dr. Cooke in the subsequent chapters. We notice that 

 the author still apparently retains the opinion that Lichens are to be regarded as a group dis- 

 tinct from Fungi on the one hand and from Algae on the other, but no new arguments are 

 brought forward to support a position which has been long ago abandoned by nearly all 

 botanists. 



Speaking generally, one. rather misses in these chapters the feeling a real and natural 

 relationship existing between the different groups, and in some instances, as in the Uredineue 

 and Ustilagineae, there is no effort made to trace it. This is especially disappointing when one 

 recollects the brilliant expositions of Brefeld and his disciples on these questions. But not- 

 withstanding this defect — for as such we must regard it — there is a great deal of valuable 

 matter in these pages which will not be readily found elsewhere. 



The concluding section on Distribution contains some interesting facts and generalisations, 

 and statistics are given as to the relative proportions in which the various groups are scattered 

 over the earth's surface. Thus amongst the Hymenomycetes it would appear that the more 

 fleshy species are chiefly restricted to temperate and cold climates, whilst the tough and 

 leathery forms are more especially characteristic of the tropical regions. 



The book is well illustrated with figures, and the copious bibliographies appended to the 

 chapters greatly add to the value of a work which deserves to be widely appreciated, not only 

 by " Collectors,"" for whose use it was more especially designed, but by all who are interested 

 in these lower orders of plants. 



Untersiichungcn iiber die Starkekbrner. By Dr. A. Meyer. Jena: Fischer, 1895. 



This is one of the most important and valuable monographs that have recently been 

 published, treating as it does of a somewhat small section of botanical research, which has 

 nevertheless been the subject of much controversy, and has been the subject of investigation 

 and speculation by many writers of great technical skill and critical acumen. It includes a 

 summary of the researches of previous observers, and is enriched by independent observations 

 of the author. 



The starch grain seems at first sight to offer but little scope for speculation, yet upon its 

 structure many points of great importance hang, which touch indeed the physical construction 

 of protoplasm itself, and that of the many organised structures derived from it. 



Dr. Meyer treats very carefully of the chemistry and physics of the starch grain as well as 

 of its biological peculiarities. He considers it to consist of at least two different bodies, which 

 he calls amylases, both of which are crystalline, though one of them cannot be made form 

 isolated crystals. Besides these other substances sometimes occur, which are also carbohy- 

 drates, but which are only found when the grains have been somewhat modified. It is a pity, 

 perhaps, that he has selected the term amylase for these two constituents, as the termination 

 -ose is so generally in use for sugars of various composition. 



Dr. Meyer holds that the crystalline substance is in the form of fine needles, to which he 

 gives the name trichiles, and these are arranged in the grain in a radiating form, producing 

 sphere-crystals, which are differently constituted in the several layers of the grain. The various 

 physical properties which the latter presents are of course consistent with this view of its structure. 

 The absorption of water which can so easily be brought about by the action of weak alkalis, etc. , 

 is discussed at some length. In the author's opinion it is brought about by the actual taking 

 up of water by the crystalline trichites, and not by its intercalation between them ; we have 

 therefore a view opposed to the older theory of the micellae put forward so many years ago by 

 Naegeli. Dr. Meyer does not, however, deny the possibility of water being taken up and held 

 by whatever lies between the crystals. 



The fate of the starch grain after its formation, the action of diastase upon it, and the 

 many possible reactions leading to the appearance of the various dextrins are also very fully 

 discussed. This section of the work in particular will be of great interest to all students of 

 vegetable physiology. 



In the chapters devoted to the formation and growth of the starch grain some new views 

 are advanced which will perhaps not be readily accepted by other workers in this field. He 

 supports very strongly Schimper's views of the action of the leucoplast, but he states that the 

 formation of the grain is always inside the corpuscle. Though this has long been recognised 

 as happening sometimes, it seems difficult to reconcile certain cases of not uncommon occur- 



