October 2']^ 1898] 



NA TURE 



^Zl 



summer and begins to form its reproductive cells in July. The 

 tetraspores are produced throughout the season, but the sexual 

 cells show a remarkable periodicity. The author described the 

 fertilisation of the oospheres by the motile antherozoids, and 

 expressed the opinion that there are strong reasons for con- 

 cluding that the factor which determines the maturation 

 and liberation of the sexual cells, and the fertilisation of 

 the oospheres, is the amount of illumination to which the 

 plants are exposed. 



Prof. Phillips, of Bangor, contributed a paper on the 

 form of the protoplasmic body in certain Floridece. In 

 Ceramiwn rubrum and other species a strong strand of 

 protoplasm runs along the axial cells from pit to pit. In Dasya 

 coccinea, the branches of limited growth run out into pointed 

 uncorticated filaments, the cells of which are large. Across the 

 vacuole of these cells running from pit to pit occurs a thread of 

 protoplasm much more delicate than the corresponding structure 

 m Ceramium. In Callithamnion byssotJes, threads of proto- 

 plasm, which exhibit incessant movement, radiate from a 

 cushion lying over the pit and end blindly on the vacuole. All 

 these phenomena point to the great physiological importance of 

 the pit-communication between cell and cell. 



Prof. Errera, of Brussels, communicated the results of some 

 recent work on the structure of the yeast cell ; his investigations 

 led him to the following conclusions: (l) a relatively large 

 nuclear body exists in each adult cell ; (2) young cells contain no 

 such body ; at a later stage the old nuclear body divides, one of 

 its two daughters wanders through the narrow connecting 

 channel into the young cell ; (3) after the division is complete, 

 the two cells are kept together by a mucilaginous neck-shaped 

 pedicel ; (4) carbohydrates are stored up in yeast in the 

 form of glycogen, which accumulates or disappears from 

 the vacuoles very rapidly, according to conditions of nutrition 

 and growth. 



Mr. Harold Wager also presented a communication on the 

 same subject ; he referred to the existence of a deeply stainable 

 body, regarded by most observers as a nucleus, and of a vacuole 

 in close contact with the nucleus. During the division of a cell 

 a portion of the nucleus and of the vacuole passes into the 

 daughter-cell. Mr. Wager pointed out certain errors in the 

 work of Hieronymus ; and expressed the opinion that the 

 "nucleus" of the yeast possibly represents an early stage in 

 the development of the vegetable nucleus ; it might be fitly desig- 

 nated a proto-nucleus. Mr. Wager also gave an account of his 

 researches on the rare fungus Polyphagus eugleita, a parasite on 

 Etiglena viridis. The material was obtained Irom a filter-bed 

 at Keighley. Mr. Wager was able to follow in detail the methods 

 of spore and zygospore formation ; he noted the interesting fact 

 that the male cell is larger, and possesses a larger nucleus than 

 the female cell. 



Prof. Marshall Ward gave an account of a new potato disease 

 which appears to be fairly common, but has hitherto usually 

 been confounded with the disease caused by Phytophthora. The 

 pathology of the disease was dealt with, and the author referred 

 to certain external symptoms which enable a practised eye to 

 distinguish diseased plants from those suffering from the attacks 

 of Phytophthora. An interesting feature of the disease is that 

 the fungal hyphw appear to prepare the way for the entrance of 

 bacteria and other organisms into the tissues of the host-plant. 

 The same author contributed a second paper, in which he 

 described the action of Pemcilliitm as a wood-destroying fungus. 



Mr. Trow, of Cardiff, gave an account of the cytology and 

 reproduction of Achlya americana var. cambrica. He de- 

 scribed the nuclear division in the oogonium and antheridium ; 

 also the occurrence of fertilisation as in Saprokgnia viixla and 

 S. die Una. 



Mr. Ellis, of Cambridge, contributed a note on a method of 

 obtaining material for illustrating smut in barley. 



Pteridophytes and Gymnosperms [Pecent and Fossil). — Mr. 

 Lang announced the discovery of the prothallus of Lycopodium 

 clavatuni. A few prothalli were found wholly imbedded in the 

 peaty soil underlying a patch of moss ; three of them bore young 

 plants, and a number of slightly older plants, the prothalli of 

 which had disappeared, were found in the same spot. The 

 prothalli, which present a general resemblance to those of 

 Lycopodium annotinuin, are of considerable size, completely 

 devoid of chlorophyll, and fairly well provided with rhizoids. 

 Their form is that of a thick fleshy cake, which soon becomes 

 thrown into folds by the unequal growth of the margin. The 



NO I 5 13, VOL. 58] 



sexual organs are borne on the upper surface ; both antheridia 

 and archegonia may be present at the same time. 



Dr. Scott gave a short account of some of his recent work on 

 the anatomy of Coal-measure plants ; the most important of his 

 contributions was a description of the structure of a new form 

 of the genus MeduUosa from the Lower Coal-measures of Lanca- 

 shire. This extinct type of Palaeozoic plants has not hitherto 

 been recorded from a British locality, and has not previously 

 been found in rocks of Lower Coal -measure age. The material 

 on which the description was founded was obtained by Mr. 

 Lomax, and the excellent sections, of which micro-photographs 

 were shown on the screen, were prepared by this able worker. 

 Dr. Scott showed that the type of structure represented by the 

 Lancashire MeduUosa is that of a polystelic Heterangium which 

 bore Myeloxylon petioles. The same author exhibited photo- 

 graphs of an unusually fine specimen of the Halonial branch o. 

 a Lepidodendron, allied to Z. fitliginosum, recently discovered 

 by Mr. Lomax. Other contributions by Dr. Scott dealt with an 

 English example of the interesting Palaeozoic fern Botryopteris, 

 and with a remarkably fine example of Zygopteris from the 

 Williamson Collections of Coal-measure plants in the British 

 Museum. 



Mr. A. C Seward described the external features, internal 

 structure and geological history of the Malayan fern Matonia. 

 The anatomical investigation was founded on some material re- 

 ceived through the kindness of Mr. Shelford, of the Sarawak 

 Museum. The stem of Matonia pectinata is characterised by 

 an arrangement of vascular tissue which appears to be unique 

 among recent ferns ; there are two annular steles, and occasion- 

 ally also an axial strand of xylem and phloem traversing the 

 creeping rhizome. The genus Matonia has usually been re- 

 garded as a type apart, and the anatomical characters emphasise 

 the isolated position of the genus. The two living species of 

 Matonia are no doubt the survivors of a tribe of ferns widely 

 distributed during the Rhsetic and Jurassic periods. 



Mr. C. E. Jones, of Liverpool, contributed a paper on the 

 anatomy of the stem of certain species of Lycopodium ; his 

 communication was of the nature of a preliminary note on the 

 subject of the general anatomical investigation of Lycopodium, 

 on which he is at present engaged. 



Mr. Pearson, of Cambridge, described the apogeotropic roots 

 of the Australian Cycad Bowenia spectabilis ; he drew attention 

 to the occurrence of colonies of Anabana in the intercellular 

 spaces of the cortex. 



Physiology and Natural History. ^^roi. Errera discussed the 

 theoretical calculation of an osmotic optimum. Recent re- 

 searches made by Dr. F. Van Rysselberghe, of Brussels, have 

 shown that vegetable cells generally answer an osmotic stimulus 

 by an appropriate osmotic reaction, and that the relation be- 

 tween stimulus and reaction follows, within wide limits, the 

 "law of Weber." Hence results the possibility of predicting 

 the existence and value of an osmotic optimum. The same 

 author also contributed a note on the unit to be adopted for 

 osmotic measurements. 



Mr. Francis Darwin read a paper of special interest on the 

 Knight-Darwin Law. (This paper is printed in full in another 

 part of the present number.) 



Prof. Reynolds Green gave an account of some results which 

 he had obtained confirmatory of Buchner's work on the enzyme 

 of the yeast plant. Prof. Green found that if the yeast ex- 

 perimented on is in a state of active fermentation, the alcohol- 

 producing enzyme can be procured as Buchner has stated. He 

 described the method of investigation adopted, and concluded 

 by stating that the enyzme obtained from yeast agrees in an 

 important respect with other enyzme. 



Prof C. de Candolle, of Geneva, gave the results of a ccwi- 

 prehensive comparative study of peltate leaves, with special 

 reference to the number of species possessing such organs, their 

 distribution among the various natural orders, and their mode 

 of growth. 



Mr. Burkill, of Kew, dealt with changes in the sex of 

 willows. In the genus Salix flowers of both sexes are oc- 

 casionally present in the same catkin, and the sexual organs are 

 sometimes found to be intermediate in structure between 

 stamens and carpels. Mr. Burkill gave the results of his ex- 

 amination of an extensive series of specimens and published 

 records. 



Mr. S. T. Dunn contributed some notes on the origin of 

 railway-bank vegetation. 



