922 



NA TURE 



[December 22, 1923 



Toumcfort'8 herbarium,— M. D. ZaleMky : On new 

 HDccics of Pennian Osmundacea!. An extension of 

 Kid»ton and Gwynnc-Vaughan'» work on the anatomy 

 of Permian Osmundaceae from Kussia. Ferns of 

 thiH afhnity in Permian timcH had a solid wood in 

 the stem, tliflferentiatt-d into an outer zone of normal 

 trachcides and an inner core of short, wide elements 

 The l<;af-trace, on its outward course, changes from 

 mesMirch to endarch structure. The Jinatomy is 

 described in liathypieris rhomboidahs (in which the 

 stele was previously unknown), in two new species 

 of Thamnoptcris (T. Kidstoni and T. Gwynne- 

 Vau^hant), and in a new species of Zalesskya (Z. 

 urahca) which may be a young state of Z. gracilis. — 

 C. L. Withycombe : On the function of the bladders 

 in Utricularia vulgaris Linn. The bladders are not 

 pa.ssive traps, but capture prey by active movement 

 in resjxjnse to stimuli. The valve is a continuation 

 of the wall ; it is two cells in thickness, and closes 

 the mouth completely when its free margin is applied 

 to the collar. It consists of three ill-defined regions ; 

 marking the third or marginal flap are four tapering 

 biccllular hairs which are sensory. The quadrifid 

 hairs lining the bladder constantly ab.sorb the fluid 

 within, until equilibrium is reached between the 

 internal negative pressure and the osmotic tension 

 which can be exerted by the cell contents of the 

 hairs. There is now a considerable tension upon the 

 valve, tending to pull it inwards. This is prevented 

 by a cushion of specialised cells within the collar. 

 Chily an upward movement can possibly release the 

 valve from its catch, and this is brought about by 

 touching he sensory hairs. 



Eugenics Education Society, December 14. — Prof. 

 E. W. MacBride in the chair. — A. S. Parkes : Some 

 aspects of reproduction considered in relation to 

 eugenics. Inherent constitution is of prime import- 

 ance from a eugenical point of view, but the conditions 

 under which reproduction takes place may have the 

 effect of limiting or augmenting the development of 

 the hereditary qualities. If reproduction takes place 

 under bad conditions, the fullest expression of the 

 inherited characteristics will be hindered. Conditions 

 obtaining during the maturation of the germ cells and 

 during the gestation of the foetus constitute the most 

 potent of environments. The age of the mother is 

 probably one of the most important factors governing 

 the efficiency of the secondary sexual organs of the 

 female for reproduction, and this is especially true 

 of first births. The optimum age for reproduction 

 seems, in the female, to be between twenty and 

 thirty years, and first pregnancies occurring much 

 after this age are attended by great probabilities of 

 mishap. 



Cambridge. 



Philosophical Society, November 12. — Mr. C. T- 

 Heycock, president, in the chair. — P. Lake : Wegener's 

 theory of continental drift. 



November 26. — Mr. C. T. Heycock, president, in the 

 chair. — J. Barcroft and H. Barcroft : The haemoglobin 

 of Arenicola. The a band of oxy-haemoglobin in Areni- 

 cola is 18 Angstrom units nearer the blue than in human 

 blood, and the o band in carboxy-haemoglobin 12 

 Angstrom units nearer the blue than in man. The 

 pigment in Arenicola has a greater affinity both for 

 oxygen and carbon monoxide than in the mammalia. 

 The oxygen capacity in Arenicola is approximately 

 o-oi c.c. of oxygen per hour, an amount which is of 

 the same order as that necessary to maintain the 

 respiration of the worm whilst its hole is closed at 

 low water. — C. Shearer : Direct measurements of 

 axial gradients in embryonic tissue. — J. B. S. 

 Haldane : A mathematical theory of natural and 



NO. 2825. VOL. I 12] 



artificial selection. Ft. I. The effect of select 

 on the competition of Mendelian populations 

 certain simple cases is investigated by means 

 finite difference equations. Sek»ction produces lil 

 change in the population when the receastves 

 few in number, except in the cases of tnl 

 aiisortative mating, and sex-linked inhentance.- 

 H. Munro Fox: (i) The spawning of echinoids. The 

 extrusion of the genital products of echinoid^^ "^ ''"'• 

 to the contraction of muscle fibres in the gon.r 



The contraction of these muscles can be arii: 



stimulated and spawning thus induced. A spawning 

 male stimulates ripe individuals of both sexes which 

 are in the neighbourhood to spawn. After spawning, 

 Strongylocentrotus lividus re-forms ripe eggs in nine 

 days at a temperature of I7°-19°. (2) The n;- 

 of a Red Sea crab through the Suez Canal. A 

 pelagicus commenced to migrate through tli 

 Canal in 1893, twenty-four years after the (..mil 

 was op>ened, and reached Port Said in 1898. The 

 crab has now spread along the Mediterranean coasts 

 to Alexandria and to Haifa. — N. J. G. Smith : The 

 parasitism of Helminthosporium grarrtimum Kab 

 [leaf-stripe disea.se of barley]. This fungus produces 

 leaf-strif>e di.sea.se without being present in the 

 growing-point, and it cau.ses death if that |X)int is 

 reached. The fungus penetrates each young leaf 

 (and finally the chaffs of the developing ear) from 

 the enveloping sheath, the first sheath bemg infected 

 from conidia, mycelium, or perithecia borne on the 

 seed or elsewhere. — R. N. Salaman : A leaf index as 

 a help to the identification of jxjtato varieties. The 

 first lateral leaflet on the left of the midrib of each 



leaf is measured, and its index -; — — i- x 100 calcu* 



length 



lated. The leaf index of a variety must be ascer- 

 tained from adult leaves on a healthy plant. The 

 variation of the index within any given variety* is a 

 normal one and represented by a normal frequency 

 curve. The probable error of the difference of two 

 means of 20 each is 0-7. A difference of two units 

 in the index may be considered as of significance. 

 Of 65 varieties of which the index was measured, 

 the value of the latter varies between 50 and 72. 

 Neither the place of origin of seed tubers, nor the 

 locality where the plants are raised, has any effect 

 on the leaf index, provided that the plants are healthy. 

 The leaf index is a constant for each variet}'. 



Dublin. 



Royal Dublin Society, November 27. — Prof. E. .\. 

 Werner in the chair. — F. W. R. Brambell and J. B. 

 Gatenby : On the supposed homology of the Golgi 

 elements of the mammalian nerve cell, and the 

 nebenkem batonettes of the genital cells of inverte- 

 brates. The Golgi apparatus in tlie smallest neurones 

 of Helix is in the p>erinuclear extra-centric p)osition, 

 surrounding an archoplasmic sphere. In larger 

 neurones it becomes dispersed around the nucleus and 

 the individual elements become much more numerous. 

 Basophil granules, probably representing the tigroid 

 body, and also lecithin (?) granules, are described in 

 the neurones. In silver preparations dark zones are 

 found around the Golgi elements. These probably 

 represent a product of its activity. Long and some- 

 times branched Holmgren canals were found in the 

 neurones. They were separate and distinct from 

 the Golgi elements. They may be processes of the 

 subcapsular cells. From the jX)sition occupied by the 

 apparatus in nerve and germ-cell, from its similarity 

 of micro-chemical reaction in both, and from embryo- 

 logical evidence, it is believed that the nebenkem 

 batonettes of the invertebrate germ-cells are homo- 

 logous to the Golgi network of the mammalian neurone 





