ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 271 



(3) In this view both the action of microbes and the liberation of 

 nitrogen either in the free state, or in the lower oxides or ammonia, must 

 be regarded as simply forms of decay. They would thus be not essential 

 to germination and growth, but accessory phenomena like the zymotic 

 diseases that attack higher organisms. 



EiFects of the Temperature of Melting lee on Germination.* — From 

 experiments performed on a number of seeds, M. C. De Candolle concludes 

 that it is impossible for germination to take place at the freezing-point 

 when care is taken that there be no local heating of the soil in contact with 

 the seeds themselves. 



Desiccation of Seeds of Aquatic Plants.t— Prof. F. Ludwig calls atten- 

 tion to Fritz Miiller's observation, that the seeds of some aquatic plants, 

 such as Eichhornia and Heteranthera, seemed to require desiccation as a 

 preliminary to germination. Some seeds of Mayaca fluviatilis, dried for 

 six weeks during their conveyance from F. Mtiller to Professor Ludwig, 

 germinated immediately after being sown, while others of the same lot, 

 sown directly in water by F. Miiller, had made no progress even after the 

 lapse of three months. A. Braun noted a similar necessity for desiccation 

 in the alga Chlamydococcus pluvialis. Fritz Miiller notes the case of 

 Pistia, where it seems that the seed must come to the surface and in contact 

 with the air before germination ; if this be prevented by entanglement, &c., 

 germination does not take place. 



Birds as Disseminators of Seeds.| — Sig. A. Piccone records a list of 

 twenty- three species of plants, natives of Liguria, nearly all trees and 

 shrubs, the seeds of which are disseminated by passing through the body of 

 birds and being voided with the excrements. He notes that the gizzard is 

 wanting in the greater number of birds of passage and in those which live 

 on insects or on soft and fleshy fruits. 



(4) Growtli. 



Correlation of Growth.§ — Dr. M. Kronfeld gives examples of Goebel's 

 law of correlation of growth, viz. that if any organ is suppressed, the organ 

 dependent on it will grow more vigorously in order to make up the loss. 

 He found this to take place to a remarkable extent with the stipules of 

 Vicia Faha when the leaves had been removed. With the small narrow 

 stipules of Phaseolus multiflorus, Bosa semperflorens, JRuhus fruticosus, and 

 Idseus, Sida Napsea, Trifolium filiforme, Vrtica urens, and the leafy 

 auricles of Pyrethrum indicum, no corresponding increase took place. In 

 Pyrus Malus, in one experiment out of five, one stipule increased in super- 

 ficies about 100 per cent. With Pisum sativum the leaves and stipules 

 each grew more rapidly when the other was removed, and flowers were 

 produced in both instances. 



Terminal Growth of the Root in Nymphaeacese.H — In addition to the 

 points of difference already recorded between the Nelumbese and the true 

 NymphseacesB, M. P. Van Tieghem points out that in the former the root- 

 cap and piliferous layer of the root are derived from the same initial cells, 

 which are independent of those of the cortex ; while in the latter the root- 

 cap is altogether independent in its origin of the piliferous layer which 

 proceeds from the same initial cells as the cortex. This point is of con- 



t * Ann. Sci. Phys. et Nat., xvi. (1886) pp. 322-3. 

 t Biol. Central., vi. (1886) pp. 299-300. 

 t Nuov. Giorn. Bot. Ital., xviii. (1886) pp. 286-91. 

 § Bot. Ztg., xliv. (1886) pp. 846-9. 

 II Bull. Soc. Bot. France, viii. (1886) pp. 264-5. 



