264 



NATURE 



\yuly 29, 1875 



Smith, F.L.S. These were identified with the bodies which 

 Mr. Berkeley had lately regarded as a species oi Frotomyces, and 

 the cause of a new malady in the potato. The following are the 

 principal points in this very important communication : — On re- 

 ceiving authentic specimens of diseased plants from Mr. Barron, 

 Gardener-in-Chief to the Society, the brown spots on the potato- 

 leaves at once called to mind the figures of some species of Fro- 

 tomyces, and the dimensions agreed tolerably well with some 

 described plants of that genus, but the spots, when seen under a 

 high power, appeared very unlike any fungus, and they were very 

 sparingly mixed with other bodies much smaller in diameter, and 

 with a greater external resemblance to true fungus spores. These 

 latter spore-like bodies were of two sizes — one transparent and of 

 exactly the same size as the cells of the leaf (and therefore very 

 easily overlooked), and the other dark, reticulated, and much 

 smaller. A few mycelial threads might be seen winding amongst 

 the cellular tissue. The author's opinion, therefore, was soon 

 formed that the " new " potato disease was no other than the old 

 Feronospora infesians in an unusual and excited condition. That 

 climatic conditions had thrown the growth of this fungus forward 

 and out of season was probable ; but the idea that the pest would 

 not at length attack all and every sort of potato seemed un- 

 reasonable, though the more tender sorts might be the first to 

 suffer. From day to day the diseased leaves and stems and tubers 

 were kept between pieces of very wet calico, in plates under 

 glass, and it was immediately noticed that the continued moisture 

 greatly excited the growth of the mycelial threads. So rapid 

 was now the growth of this mycelium, that after a week had 

 elapsed some decayed parts of the lamina of the leaf were tra- 

 versed in every direction by the spawn. In about ten days the 

 mycelium produced a tolerably abundant crop, especially in the 

 abortive tubers, of the two-sized boaies previously seen in 

 the fresh leaves. The larger of these bodies Mr. Smith was 

 disposed to consider the "oospore" of the potato fungus, and 

 the smaller bodies as the ' ' antheridia " of the same fungus, 

 which are often terminal in position. The filaments of the latter 

 are commonly much articulated, and sometimes more or less 

 moniliform or necklace-like. Both oospore and antheridium are 

 very similar in nature and size to those described as belonging to 

 Feronospora alsinearum and F. umbelli/erarum, and this is another 

 reason (beyond the occurrence of undoubted F. injestans on potato- 

 leaves at the beginning of June) why he was disposed to look upon 

 these bodies as the oospore and antheridium of the potato fungus. 

 The larger bodies are at first transparent, thin, pale brown, fur- 

 nished with a thick dark outer wall, and filled with granules ; at 

 length a number (usually three) of vacuities or nuclei appear. 

 The smaller bodies are darker in colour, and the external coat is 

 marked with a few reticulations, possibly owing to the collapsing 

 of the outer wall. At present he had been unable to detect any 

 fecundating tube (described as belonging to the antheridium of 

 other species of Feronospora), but he had observed the two 

 bodies in contact in several instances. After fertilisation has 

 taken place, the outer coat of the oospore enlarges, and appears 

 to be cast off. Both antheridium and resting-spore are so slightly 

 articulated to the threads on which they are borne that they are 

 detached by the slightest touch, but with a little care it is not 

 reaDy difficult to see both bodies in situ ; and my observations 

 lead me to think that conjugation frequently takes place after 

 both organs are quite free. The antheridia and oospores are 

 best seen in the wettest and most thoroughly decomposing tuber, 

 but they occur also in both the stem and leaf. The author was 

 also disposed to regard Montague's Artotrogus as identical with 

 the resting-spore of Feronospora infestans, an opinion which had 

 long been held by Mr. Berkeley. 



Paris 

 Academy of Sciences, July 19.— M. Fremy in the chair. — 

 The following papers were read : — On M. Espy's meteorological 

 theory, by M. Faye. — On the continuation which it will be 

 necessary to make of experimental researches on plasticodyna- 

 mics, by M. de Saint-Verant. This new branch of mechanics 

 treats of the internal motions of solid bodies in a state of plas- 

 ticity. M. Tresca added some remarks on the same subject. — 

 Experimental and clinical considerations on the nervous system 

 with regard to its function in actions governed by the sensitive, 

 instinctive and intellectual faculties, as well as in the so-called 

 voluntary locomotive actions, by M. Bouillaud. The author 

 arrives at the following conclusions : — The cerebrum and the 

 cerebellum are both absolutely necessary for all actions v/hich 

 are governed by the various faculties of mind or intelligence. 

 The cerebellum is the seat of co-ordination of the movements of 



walking, the cerebrum being the seat of the co-ordinating centres 

 of the movements necessary for the execution of a great number 

 of intellectual actions, speech in particular. — On a distinc- 

 tion between natural and artificial organic products. The 

 author repeats the distinction made by him in i860, in reply to 

 a statement by M. Schutzenberger. This distinction is that 

 natural bodies are always unsymmetrical. — Observations relating 

 to M. Hirn's communication of June 23. Importance of basing 

 the new theory of heat on the hypothesis of the vibratory state 

 of bodies, by M. A. Ledieu. — Note on the chronology and 

 geography of the plague in the Caucasus, in Armenia, and in 

 Anatolic during the first half of the nineteenth century, by 

 M. J. D, Tholozan. — On the development of the spiny rays in 

 the scale of Gobius Niger, by M. L. Vaillant. — On d' Arrest's 

 periodic comet, by M. Leveau. — Observations of Jupiter's satel- 

 lites during the oppositions of 1874 and 1875. Determination of 

 their differences of aspect and of their variation of brilliancy, by 

 M. Flammarion. In size the decreasing order is III., IV., I., II. 

 Intrinsic luminosity for equal surfaces I., II., III., IV. Vari- 

 ability in decreasing order IV., I., II., III. — Note on magnetism; 

 reply to an observation of M. Jamin, by M. J. M. Gaugain. — 

 Oxy-uvitic and the cresol derived from it, by MM. A. Oppen- 

 heim and S. Pfaff. The cresol is metacresol. — On a compound 

 of methyl oxide and hydrochloric acid, by M. C. Friedel. — On the 

 diethylic ether of xanthoacetic acid, by MM. C. O. Cech and A. 

 Steiner. — On the estimation of carbon disulphide in the sulpho- 

 carbonates of potassium and sodium, by MM. David and 

 Rommier. — On the mode of action of the pillars of the dia- 

 phragm, by M. G. Carlet. — On the reproduction of eels, by M. 

 C. Dareste. — The morphological elements of the oblong leaves 

 of the monocotyledons, by M. D. Clos. — On a claim of 

 priority relative to a fact of botanical geography, by M. Ch. 

 Contejean. — During the meeting M. Mouchez was elected a 

 member of the Astronomical section to replace the late M. 

 Mathieu. 



BOOKS AND PAMPHLETS RECEIVED 



British.— Chambers' Encyclopaedia. lo vols., new and revised edition 

 (W. and R. Chambers). — Reports of the Medical Officer of the Privy Council 

 and Local Government Board. New Series, No. 3 (.^pottis»oode). — On the 

 Inequalities of the Earth's Surface viewed in connection with the Secular 

 Cooling: Osmond Fisher, M.A. (Cambridge Philosophical Transactions). — 

 Flora of Eastbourne : F. C. S. Roper, F.L.S. (Van Voorst). — Travels in 

 Portugal : John Latouche (Ward, Lock, and Tyler) — Second Supplement 

 to Watts's Dictionary of Chemistry (Longmans). — Transactions of the Man- 

 chester Geological Society, Vol. xiii. Part 10. — Health in the House : Cathe- 

 rine M. Buckton (Longmans). — Hydrology of South Africa: J. Croumbie 

 Brown, LL.D. (H. S. King and Co.) — Rudiments of Geology: Samuel 

 Sharp, F.S.A., F.G.S (E. Stanford). -The Skull and Brain; thcr Indica- 

 tions of Character and Anatomical Relations : Nicholas Morgan (Longmans). 

 North Staffordshire Naturalists' Field Club Addresses, Papers, &c. — On the 

 ScnsatioBS ot Tone as a Physiological Basis for the Theory of Music, by H. 

 Helmholtz; translated by A J. Ellis, F.R.S. (Longmans). — Reports and 

 Proceedings of the Miners' Association of Cornwall and Devon for 1874. 



CONTENTS Pags 



Practical Physics 245 



Carus and Gerstaecker's " Handbuch der Zoologie." By Prof. 



E. Ray Lankestek, F.R.S 247 



Our Summer Migrants 249 



Our Book Shelf : — 



Dymond's " Meteorology of West Cornwall and Scilly " . . . . 250 

 Letters to the Editor : — 



Vibrations of a Liquid in a Cylindrical Vessel. — Lord Ravleigh, 



FR.S 25t 



Insectivorous Plants — Dr. Lawson Tait 251 



Curious Phenomenon in the Eclipse of 1927. — Rev. S. J. Johnson^ 252 

 Spectroscopic pr^visioi of Rain with a High Barometer. — Prof. 



Piazzi Smyth 252 



Sea-power — A. C 253 



Our Botanical Column : — 



The Adelaide Botanic Garden 253 



Sumbul Root 253 



The Progress of the Telegraph, IX. (IVith Illustrations) ... 254 

 Our Astronomical Column : — 



The Transit of Venus, 1882 December 6 256 



The Sun's Parallax 256 



A Third Comet in 1813 (?) 256 



The Great Comet of 1843 257 



D'Arrest's Comet in 1877 257 



The International Geographical Exhibition 257 



The Regulation of Rivers 259 



The Gigantic Land Tortoises of the Mascarene and Gala- 

 pagos Islands, II. By Dr. Albert Gunther, F.R.S 259 



Notes ... 261 



Societies and Academies 263 



Books and Pamphlets Received 264 



Errata. — Page 232, col. i, line 24 from bottom, for "currents" read 

 " cumuli " ; line 22 from bottom, for "lovely " read " lowly." 



