ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 547 



examined after some days. They had put out a quantity of new roots, 

 but on none of these were there any tubercles. The bacterioid bodies 

 bad now assumed the form o^ true bacilli, and bad become elongated 

 and septated, and bad transferred themselves into isolated somewhat 

 swollen cells. The tubercles be considered unquestionably as i)atho- 

 genous products of the nature of bacteriocecidia, and to have no 

 importance whatever in su2)plying nutriment to the plant. The plants 

 so affected he found produced no fruit, probably from au insufficiency in 

 the supply of phosphorus and maguesia. 



Tubercles of Ruppia and Zannichellia.*— Herr E. Hisinger con- 

 firms Goebel's statement that the tubers frequeutly found on Buppia 

 rostellata and Zannichellia pohjcarpa are caused by a parasitic fungus 

 (Myxomycete) Tetramyxa parasitica. 



Lateral Roots of Monocotyledons.f — In continuation of his re- 

 searches on this subject, Sig. A. Borzi now describes the structure of 

 the lateral roots in Phormium tenax, Agapanthus umhellatus, Dracsena 

 Hendersoni, Cordyline stricta, Agave mexicana, and Fourcroya gigantea, 

 all belonging to bis fourth type. 



B. Physiolog^r. J 

 (1) Reproduction and Germination. 



Intracellular Pang'enesis.§— Prof. H. de Vries proposes a modifica- 

 tion of Darwin's provisional hypothesis of pangenesis. He assumes that 

 the nucleus of every cell usediu pro2:)agatiou contains all sorts of pangens 

 of the species of animal or jjlant to which it belongs. As all other 

 nuclei of the full-grown being owe their origin to repeated divisions of 

 the first, they can all be in possession of a complete set of pangens, 

 which can propagate themselves when a division takes place. In the 

 nucleus the greatest part of them remain inactive through life, with the 

 exception ouly of those pangens which determine the visible characters 

 of the nucleus itself, such as its special mode of division, &c. All 

 other organs of the protoplast essentially contain only pangens corre- 

 sponding to the characters which they are capable of displaying. It is, 

 however, by no means necessary that they should be all at all times in 

 an active sttite; thus plastids are in some cases known to exhibit alter- 

 nately the power of forming starch and some colouring matter. But 

 usually no doubt these organs contain a large number of active pangens. 

 Inactive pangens from the nucleus can migrate to those other oro-ans of 

 the protoplast whose characters they represent ; they c m again propa- 

 gate themselves here, and in most cases sooner or later become active, 

 thus bringing to light certain characters. This migration, as shown by 

 the facts of sexual reproduction, must occur soon after fecundation has 

 taken place ; but there is no reason why it could not happen in many 

 other i)hases of development, perhaps even every time a cell divides. This 

 migration of pangens may be effected by the movements of protoplasm. 



* Medd. af Soc. Faun, et Flor. Fenii., xiv. pp. 53-7 (10 pis.). Cf. Bot. 

 Ceutialbl., xsxvii. (1889) p. 316. Cf. this Journal, 1885, p. 292. 



t Malpighia, ii. (1S88) pp. 394-402. Cf. this Journul, 1888, p. 762. 



X This subdivision contains (1) Eeproduction and Germination; (2) Nutrition 

 and Growth (including Jloveraents of Fluids) ; (3) Iiritability ; and (4) Chemical 

 Changes (including Respiration and Fermentation). 



§ ' Die Intracellulare Pangenesis,' 8vo, Jena, 1889, 212 pp. 



