214 



NA TURE 



[Jan. 8, 1885 



book, as is well known, proved to be a masterpiece of 

 industrious research, accurate treatment of facts, and 

 critical sifting of details ; its influence soon became 

 apparent, not only on the best teaching and text-books of 

 our time, but also on those engaged in original research 

 in various directions. This marked influence was not 

 confined to Germany, but affected the teaching in this 

 country also ; and some of us were so fortunate as to 

 come under that influence before more antiquated methods 

 of treatment had rendered difficult the task of receiving 

 the new impressions. 



Mr. Bower and Dr. Scott have now prepared a transla- 

 tion of this treatise, and those best acquainted with the 

 original will be foremost in congratulating them, not only 

 for having placed the work in the hands of English 

 workers and students, but also for the manner in which it 

 has been accomplished. 



In commenting upon the plan of the book, it should be 

 borne in mind that the basis of classification is anatomy, 

 and anatomy only, and this accounts for many peculiarities 

 in the mode of treatment. 



The introduction sets this forth clearly, and shows the 

 kind of difficulties to be avoided in the scheme. Students 

 will gain by carefully reading this able introductory por- 

 tion, which contains an admirable account and criticism 

 of the relations of the tissues to the meristem from which 

 they are derived, and the vexed question as to the best 

 mode of classifying the systems of tissue in mature parts. 

 The great difficulty of course is in the case of what Sachs 

 terms the "fundamental tissue" — i.e. the tissue which 

 remains after the dermal tissue and fibro-vascular system 

 have been removed. De Bary finds it necessary to cut 

 this up into several forms and systems of tissues, as was 

 to be expected from the mode of treatment. Sachs has 

 lately again maintained that on the whole the "funda- 

 mental tissue " is best regarded as one system. This and 

 other discussions as to the relative value of systems of 

 tissues certainly owe much to the point of view started 

 from, and it is not easy to see how De Bary could avoid 

 the further dissection of the larger systems of tissues. 



As matter of fact he is constrained to adopt six chief 

 forms of tissue, various groupings of which constitute 

 the systems of tissues. These are : (1) Cellular tissue 

 (epidermis, cork, and parenchyma) ; (2) sclerenchyma ; 

 (3) secretory structures ; (4) vessels (this word is Trachea 

 in the German, and "vessels" does not express its in- 

 tended meaning accurately) ; (5) sieve-tubes ; (6) milk- 

 tubes {i.e. laticiferous vessels). Intercellular spaces form- 

 ing the subject of an appendix. This preliminary classi- 

 fication, as would be expected, presents difficulties here and 

 there, and it will be seen that the structures designated 

 "secretory" afford exercise for the utmost ingenuity in 

 classifying them anatomically. 



Having laid down the lines along which the plan of the 

 work is to run, so far as these forms of tissue are con- 

 cerned, De Bary then proceeds to review and criticise 

 the views held as to the differentiation of the various 

 groups of tissues from definite layers or portions of the 

 meristem of the growing-point. Hanstein's classification 

 into dermatogen, plerome, and pleriblem is well known, 

 as is also the calyptrogen of Janczewski. We cannot here 

 enter into details, but must refer the student to this excel- 

 lent summary, merely stating that the facts do not allow 



of Hanstein's classification being extended to all the 

 cases, though it must be admitted as true for very many. 

 Nor have later investigators succeeded in establishing a 

 system of classification of the tissues comparable to that 

 of the animal embryologist. This of course complicates 

 the matter, and accounts in part for the plan followed in 

 the second part of the book, which treats of the arrange- 

 ments of the forms of tissue referred to above, and of the 

 changes in their primary arrangement brought about by 

 secondary changes, e.g. growth in thickness, &c. 



In Part I. the first chapter deals with cellular tissue, 

 the portion concerned with the epidermis and its structure 

 being particularly interesting and important. De Bary's 

 account of the stomata has long been known, but many 

 facts relating to those peculiar forms known as water- 

 pores or water-stomata will be new to the student un- 

 acquainted with the original. The description of the 

 cuticle and cuticularised layers of the outer walls of the 

 epidermal cells, and the facts as to the occurrence of wax 

 on their exterior are very important, and must afford the 

 basis for all future work on these subjects. A striking 

 example of De Bary's critical power and ability to deal 

 broadly as well as in detail with large series of facts are 

 evident in his remarks on those troublesome organs known 

 as glands. It may well be doubted whether we shall ever 

 have a satisfactory classification of the various "secretory 

 structures " on anatomical grounds solely ; it must be 

 admitted, however, that the most satisfactory account of 

 these bodies, as a whole, is given in the present book. 

 De Bary limits the term gland to epidermal secretory 

 organs — all others are to have definite names implying 

 their different position, &c. This necessitates the sepa- 

 rate treatment of reservoirs of secretions, and laticiferous 

 vessels as contrasted with epidermal or dermal glands on 

 the one hand, and intercellular spaces which contain 

 secretions, &c, on the other: the difficulties arising from 

 various causes are in part met and discussed, but there 

 are some still outstanding. 



Having treated of the forms of tissue in the first seven 

 chapters, Part II. of the book commences with Chap. 

 VIII. The first section (Chaps. VIII. to XIII.) is con- 

 cerned with the primary arrangement of the forms of 

 tissue. The vascular bundles are here dealt with in great 

 detail from two points of view: (1) with reference to their 

 course or distribution in the stems, leaves, and roots ; and 

 (2) as regards their structure. The first aspect of vascular 

 bundles is almost unknown in England, and most teachers 

 have ignored it altogether. It is important, however, and 

 although they must not be ranked or compared with 

 structures occurring in other organisms, we must not 

 forget that the supporting and conducting systems of 

 a higher plant are represented by its wood and trachea;, 

 while its sieve-tubes have equally important duties to 

 perform. This being so, there is no less reason for 

 studying the course and distribution of the vascular 

 bundles (and the same remark applies to laticiferous 

 vessels, reservoirs of secretion, and even strands of scleren- 

 chyma) in a plant, than for tracing the distribution of the 

 various conducting, supporting, and secreting tissues and 

 organs in a higher animal. Already the investigations 

 promise to bear fruit, as witness Koch's descriptions of 

 the course and endings of sieve-tubes in the leaves, and 

 also the various points of anatomy which throw light on 



