504 Scientific Intelligence. 



work may be interpreted as showing that the protective wood 

 which grows over wounds always exhibits a notable agreement in 

 all particulars with the heart-wood of the same plant, even shar- 

 ing its tyloses, i-esins, gums, and to a certain extent its coloring 

 matters. 



The vascular bundles which are termed " concentric " are of 

 two kinds: (1) the xylem is surrrounded by the phloem, (2) the 

 phloem is surrounded by the xylem. The first is characteristic 

 of ferns, although examples are not wanting among flowering 

 plants. Both of these kinds have been examined by Mobius 

 (Ber. Deutsch. Bot. Ges. 1887, 2), who adds to the results of his 

 special investigation a convenient synoptical table of the orders 

 in which these different types are to be seen. 



von Tavel (Ber. Deutsch. Bot. Ges. 1887, 438) gives an inter- 

 esting account of his investigation of the mechanical structure of 

 bulbs. Bulbs are, in general, reservoirs of food which grow under 

 a certain amount of pressure from surrounding soil. In some cases 

 the weight of superincumbent earth is very considerable. Under 

 these restricting pressures the bulb would become much distorted 

 were it not protected by strong mechanical elements. A study 

 of the distribution of these elements and an examination of the 

 epidermal structures of bulbs show that they have no relation what- 

 ever to the systematic place of the species, but that they are 

 strictly adaptive. 



The comparative histology of allied orders of flowering plants 

 continues to attract a considerable number of investigators, but 

 as yet without any very satisfactory results in the direction of 

 generalization. Nor can it be expected that the survey of the 

 limited fields thus far brought under observation can reveal any 

 general laws, but the value of the results of such scattered and 

 often very fragmentary histological studies cannot well be over- 

 estimated. Among those most recently published are the follow- 

 ing : Hitzemann's examination of Ternstroemiacege, Dipterocar- 

 pese, and Chlaenacese, and Saupe's investigation [Flora, 1887, p. 

 259] of the wood of the Leguminosse. The conclusions reached 

 by the latter may be briefly stated thus : (l.) It is impossible to 

 separate the suborders Papilionacese Csesalpiniacese, and MirnoseaB 

 on the basis of wood-structure. But, on the other hand, it is 

 perfectly practicable to distinguish in these suborders, closely 

 related and sharply marked groups of small sizes. And, more- 

 over, it is easy to detect, in some instances, a close anatomical 

 resemblance between two members of some of these groups, even 

 when they grow naturally under wholly diverse circumstances. 

 But their species cannot as yet be distinguished clearly by means 

 of the histological character of the wood. G. l. g. 



3. Forms of Animal Life. — A Manual of Comparative Anat- 

 omy, with descriptions of selected types, by the late G. Rolles- 

 toist, Linacre Prof. Anat. Phys., Oxford ; second edition, revised 

 and enlarged by W. H. Jackson, F.L.S., Nat. Sci. Lecturer, St. 

 John's College. 938 pp., 8vo. Oxford : 1888. (Clarendon 



