2 88 



NATURE 



\_July 1 9j 1883 



oscillations of the meniscus perfectly visible, weaker currents 

 causing a total displacement of the mercury corresponding to the 

 strength of the current, while the oscillations ot the meniscus 

 appeared only as a broad undefined rim. Dr. Martius then 

 investigated the action of induced alternating currents, the be- 

 haviour of which was much more complicated inasmuch as, 

 with equal intensity of the primary current and equal distances 

 of the induction cuds from one another, the four follow- 

 ing different cases are to be observed: (1) The current on 

 breaking contact passes through the mercury meniscus in 

 a positive or anodic direction ; (2) the current on making 

 contact passes in a cathodic direction ; (3) the current on break- 

 ing contact passes in a cathodic direction ; (4) that on making 

 contact passes in an anodic direction. All these four cases 

 which group themselves in pairs in every experiment, affect the 

 meniscus differently ; for besides the difference of the anodic and 

 cathodic current, already mentioned in the case of constant cur- 

 rent-, the current on making contact under otherwise similar 

 conditions was more effective than that on breaking contact, the 

 action of the current on the instrument being, therefore, just the 

 reverse of that on the nerves and muscles. The reason of this is 

 that in the capillary electrometer the current on making contact 

 produces a stronger polarisation than that on breaking contact, 

 on account of its longer duration. The total effect which alter- 

 nating induction currents produce on the capillary electrometer is 

 the result of the individual effects of the current, and is certainly on 

 this account very complicated, but it can be predicted acccording 

 to the rules given above for every direction, strength, and frequency 

 of the induction currents.- Prof. Kronecker demonstrated on a 

 student the audibility of the muscle tone when the muscle was 

 voluntarily contracted, by means of a pair of telephones. The 

 telephones were connee'ed with two needle-, which the student 

 placed in his biceps muscle, and the members of the Society 

 convinced themselves that at every contraction of the mu scle a 

 deep soft breathing tone was heard. 



Physiological Society, June 29. — Dr. Curt Lehmann ex- 

 plained two apparatus, which he had constructed with a view of 

 maintaining artificial respiration in animals upon which other 

 experiments are tried. The former method, which consists in 

 blowing air into the lungs by means of a motor working in a 

 certain rhythm, has the disadvantage that, in order to keep up 

 the efficiency of the ventilation, the pressure must soon be in- 

 creased, producing emphysema of the lungs, to which the ani- 

 mals succumb. Dr. Lehmann has obviated this by blowing air 

 into some receptacle by means of the motor in question, and by 

 letting it there be condensed to a certain moderate density (say 

 8 to 10 cm. of water). A second receptacle contains air in a 

 corresponding degree of rarefaction. An indiarnbber tube is 

 tied into the trachea of the animal ; this tube is forked at the 

 other end, one branch communicating with the condensed the 

 other with the rarefied air. An electric clock, which marks 

 whatever intervals of time are required, is connected l.y means 

 of a double lever with this tube, and alternately closes the one 

 or the other of the branches. Thus air is either driven into the 

 lung under a gentle pressure or is sucked out of it under the 

 same pressure. In spite of the low pressure, the ventilation is 

 perfect on account of the alternate driving in and sucking out of 

 air ; the lung of the animal is in no wise affected, and artificial 

 respiration can thus be kept up without danger for eight hours, 

 lhe second apparatus, which on the whole, after the same 

 principle, connects the lung alternately with condensed and 

 rarefied air, is constructed in a more complicited manner, as it 

 contains bells for the collection of the respiration products, for 

 the event that these may have to be examined. Both appa- 

 ratus work automatically ; the influence of the respiratory 

 motion upon the blood pressure could be shown when they 

 were used, just as easily as with animals respiring normally. 

 The special experiments in which Dr. Lehmann used these ap- 

 paratus referred to the influence of temperature upon the bacilli 

 of Septicemia. Developed in blood outside the body, the num- 

 ber of bacilli increased the more, under equal conditions other- 

 wise, the higher the temperature, up to 43° C. With animals 

 the experiments were made in such a way that in each 

 series of experiments four rabbits were vaccinated with 

 septicemic bacilli. Of these No. I was kept at 42° C, No. 2 

 at ordinary room temperature, No. 3 strongly cooled by meansof 

 water (temperature 35° C. in the interior), and No. 4 poisoned 

 with curare and cooled. No. 1 died first, although about two 

 hours before its death but few bacilli were contained in the 

 blood ; soon afterwards No. 3 died, its blood containing many 



bacilli ; a few hours later No. 2 succumbed, having attained the 

 fever temperature of 42 C. much later than No. I ; the number 

 of bacilli in its blood was moderate. No. 4 lived longest, 

 although the number of bacilli in its blood was greatest. — A com- 

 munication was then read concerning the important observations 

 made by Pruf. Pfliiger (Bonn) regarding the division of frog's 

 ova by a groove-formation after fertilisation. It is known that 

 fertilised frog's ova turn over in such a way that their black 

 hemisphere is turned upwards and the white one downwards, 

 and that the axis pa-sing through the centre symmetrically to 

 both hemispheres is perpendicular. The normal grooving now 

 begins with a division in a median plane passing through the 

 axis ; the second division is at right angles to the first, also pass- 

 ing through the axis ; the third one takes place at right angles to 

 the axis, somewhat nearer to the upper end. Prof. Pfliiger 

 prevented some fertilised frog ova from turning over by fasten- 

 ing them to glass, so that in the single ova the hemisphere axes 

 pointed in the most varied directions ; yet he found that the first 

 division in all of them was always perpendicular, without any 

 reference to the position of the axis ; the sec md and third 

 divisions of the ovum remaining in the same relative position 

 with regard to the first anomalous division as if the ova had 

 been in a normal position. The first traces of the groove of the 

 back also invariably showed themselves on the upper side of the 

 first division plane, thus frequently in the white hemisphere. 

 But later on all the ova which were fastened at the bottom 

 perished. 



CONTENTS Page 



Cholera Prospects 265 



Modern Persia. By Prof. A. H. Keane .... 266 

 Chlorophyll Corpuscles and Pigment Bodies in 



Plants. By Prof. H. Marshall Ward 267 



Our Book Shelf:— 



Brown's " Forests of England " and " French Forest 



Ordinance of 1669 " 268 



Letters to the Editor : — 



" Waterspouts" on the Little Bahama Bank — Whirl- 

 wind at Grand Cayman.— Lieut. Morris H. 



Smyth, R.N 269 



A Remarkable Meteor.— P. F. D 269 



The Function of the Sound-Post in the Violin. — R. 



Howson 269 



Waking Impressions.— Mrs. J. Maclear .... 270 



Tertiary Corals.— W. E. Balston 270 



Wild Fowl and Railways — Instinct and Intelligence. — 



Dr. John Rae, F.R.S 270 



Clouds.— R. Y. Armstrong ( With Diagrams) . . 270 

 Extraordinary Flight of Dragon-Flies.— Alfred New- 

 ton 271 



Sheet-Lightning.— W. G. Stillman .271 



Algae. By Mrs. Mary P. Merrifield 271 



Gauss and the Late Professor Smith. By R. 



Tucker 272 



Anthropology in America 273 



The Size of Atoms, III. By Sir William Thomson, 



F.R.S. (With Diagrams) «74 



Smoke Abatement 278 



Notes 2 79 



Our Astronomical Column : — 



The Total Solar Eclipse of August 28-29, 1886 . . 281 



Tempel's Comet, 1873, II 282 



Solid and Liquid Illuminating Agents 282 



The Royal Society of Canada 283 



The Hypophysis Cerebri in Tunicata and Verte- 



brata. By Prof. W. A. Herdman 284 



University and Educational Intelligence .... 286 



Scientific Serials 286 



Societies and Academies 2^7 



Erratum.— On p. 264, col. 1, line 9, for rabies read tabes. 



