620 SUMMARY OF CURRENT RESEARCHES RELATING TO 



hindered by neutral salts and destroyed by alkalies ; and it is most active 

 at a temperature of 40° C, 



4. The process of germination is started or accompanied by a trans- 

 formation of the zymogen into ferment on the absorption of water and the 

 development of vegetable acids in the cells of the seed. 



5. The ferment so developed converts the proteids of the resting seed 

 into acid albumin or parapeptone, peptone, and crystalline amides. 



6. The nitrogen travels from the cells of the seed to the growing 

 points in the form of the latter bodies, and not in that of peptone or other 

 proteids. 



7- General. 

 Myrmecophilous Plants,* — In an exhaustive treatise on this subject 

 Prof. F. Delpino distinguishes three different ways in which ants are 

 attracted to plants, viz. : — (1) By honey-glands or extra-floral nectaries ; 



(2) By the formation of special minute organs which serve to attract ants ; 



(3) By the formation of receptacles in which the ants live. Of these, the 

 first is by far the most common, the two latter occurring only in a few 

 tropical plants. In the present publication, which is the first portion only 

 of the treatise, the author enumerates a very large number of species pro- 

 vided with extra-floral nectaries, belonging to about thirty natural orders ; 

 of these the Leguminosse include the greatest number. Delpino considers 

 that ants and wasps play a most important function in the life of many 

 plants, as the most active destroyers of their greatest enemies, such as 

 caterpillars and the larvae of other insects. 



Eifects of Low Temperatures on Plants-t — Prof. W. Detmer records 

 several instances in which seeds can be exposed to very low temperatures 

 ( — 10^ C.) without being killed, though, when they do germinate, the 

 process is very much retarded. In some cases a temperature of — 17° G. 

 is not sufficient altogether to kill tissues, and this is also the case with 

 bacteria. 



Goebel's 'Outlines of Classification and Special Morphology.' J — This 

 book is an expansion of Part II. of Sachs's ' Text-book of Botany,' but is 

 in great part rewritten. The various groups of plants are taken up from 

 the Thallophytes to the Phanerogams, and the main points of their mor- 

 phology described. In Flowering Plants, the German classification of 

 Angiosperms is still retained, which differs widely from that of Benthara 

 and Hooker, universally adopted in this country. But Sachs's classification 

 of Thallophytes, dependent entirely on the mode of reproduction, is aban- 

 doned, and they are divided into five primary groups: — Myxomycetes, 

 Diatomacese, Schizophyta (Cyanophycese and Schizomycetes), AlgaB (in- 

 cluding Protococcacete and Cbaraceae), and Fungi. The work may be 

 accepted as embodying the results of all the most recent observations on 

 the structure of the various groups of plants. 



B. CRYPTOGAMIA. 



Development of Spermatozoids. § — Mr. Douglas H. Campbell describes 

 the structure and development of the spermatozoids in several species 

 belonging to the Filices, Ehizocarpese, and Muscinese. His observations 



* Mem. K. Accad. Sci. Bologna, vii (1886). See Bot. Centralbl . xxx. (1887) p. 38. 



t SB. Gcsell. Bot, Hamburg, April 22, 1886. See Bot, Centralbl., xxix. (1887) 

 p. 379. 



I Goebel, K., ' Outlines of Classification and Special Morphology of Plants.' Trans- 

 lated by H. P. V. (jlarnsey; revised by Prof. J. B. Balfour. 515 pp. and 407 figs. 

 Oxford, 1887, § Ber. Deutsch. Bot. Gesell., v. (1887) pp. 120-7 (1 pi.). 



