138 



SCIENTIFIC NEWS. 



[Aug. 10, I? 



drums, holding from 3 to 9 lbs., or in casks holding 

 more than 1 cwt. Inferior grades are packed in bags, 

 and serve for the manufacture of various concoctions. 



We are told that such figs, from their multitude of 

 " seeds," are found -useful for mixing with strawberries 

 and raspberries in the production of artificial jams, being 

 boiled up with vegetable marrows, glucose, " fruit 

 essences," and appropriate colouring matters. 



Two remarkable facts concerning the fig are not gene- 

 rally known. The fruit is not, like a plum, an orange 

 or an apple, a unitary product, developed from a single 

 blossom. Every fig contains, or has contained, within it 

 a multitude of blossoms, each of which becomes one of 

 those tiny granules found embedded in the pulp, and 

 erroneously called " seeds." 



The second memorable point is that, although the fig is 

 perfectly wholesome, the juices of the leaves and the 

 bark are somewhat poisonous, which may account for its 

 general immunity from the ravages of aphides, cater- 

 pillars, etc. Some of the near kindred of the common 

 fig tree, such as Fiats toxicaria and Ficus dcemonum, are 

 well known in India for their venomous character. 



^w^^+sf-*- 



of papers, Hectares, 



etc* 



ROYAL SOCIETY. 

 At the last meeting a paper " On the Electromotive 

 Changes connected with the Beat of the Mammalian 

 Heart,and of the Human Heart in Particular," was read by 

 Augustus D. Waller, M.D. The electromotive properties 

 of various animal tissues (muscles, nerves, glands, 

 retina), and the changes which these properties under- 

 go with activity have occupied a large share of the atten- 

 tion of physiologists during the last hundred years, since 

 the memorable observations of Galvani and of Volta 

 (1786-1798). And in recent years evidence of similar 

 electromotive changes has been sought for and found 

 even in man ; two notable experiments are quoted in 

 the physiological literature of this subject, by Du Bois- 

 Reymond and by Hermann, to show that the contraction 

 of human muscle is attended with electromotive 

 changes. It cannot be said, however, that either of 

 these experiments are free from doubt, nor that they 

 furnish anything beyond a problematical illustration of 

 facts which can be analysed only upon isolated tissues. 

 The observations, of which a brief summary was given, 

 deal with an entirely new aspect of the subject ; they 

 furnish a demonstration in man of the electromotive 

 changes which accompany each contraction of the heart. 

 The author states that it is possible, by leading off from 

 various parts of the surface of the body to a capillary 

 electrometer to observe upon animals and upon man 

 variations of potential coinciding with and dependent 

 upon the heart's beat, and he showed photographic 

 records of these variations. 



ROYAL HORTICULTURAL SOCIETY. 

 At the meeting of the Scientific Committee on July 24th, 

 Dr. H. Scott in the chair, Mr. Prowright, in acknow- 

 ledging the letter of thanks addressed to him some time 

 since by the Chairman on behalf of the Committee, made 

 the following remarks : — " It was my hope when I began 

 my cultures that the general outcome would tend to a 



lessening of the number of the species of the Uredineae. 

 This, however, is not the case; on the contrary, I feel 

 convinced that physiological investigation will show that 

 these parasitic fungi are much more numerous than we 

 at present imagine. To take one instance only, that of 

 the Uromyces, which occurs upon beans. It is now 

 generally thought that one species is common to most of 

 the Leguminosae. I have made a number of cultures on 

 this point, and find that when U.fabce from the common 

 bean haulms is placed on young plants of bean, pea, 

 Vicia cracca, V. sativa, Lathyrus pratensis, and Ervum 

 hirsuium jEcidia are only produced on the bean and pea ; 

 and further, that the Uromyces on Ervum hivsutum ap- 

 plied to the same host plants produced ^Ecidium on 

 Ervum only. In the same way the Puccinia which occurs 

 upon the Compositae is, I find, not one species, as is 

 generally supposed, but that Uredospores from Ccntaurea 

 nigra, for instance, will not affect Taraxacum officinale, 

 neither will the Uredospores of T. officinale infect Apar- 

 gia autumnalis nor Lapsana communis. Before the true 

 affinities of these species can be satisfactorily determined 

 numerous and long-continued biological investigations 

 will have to be made for the hasty grouping together of 

 the various forms, because they occur on allied host 

 plants, is as liable to error as the opposite plan of making 

 every form a species because it occurs on a different host 

 plant." 



Dr. Masters showed diagrams representing the move- 

 ments in the shoots of firs, not only of the leader shoot 

 of Abies bifida (frma), but also of the lateral shoots ; 

 while the leader shoot gyrates in irregular ellipses, its 

 point being alternately raised or depressed, the lateral 

 shoots not only move from one point of the compass to 

 another, and are elevated or depressed, but are rotated 

 on their own axis, the leaves also being raised or de- 

 pressed at various angles. These movements of shoots 

 and leaves were very complex, and in all probability de- 

 pendent on different causes. 



THE ARTIFICIAL REPRODUCTION OF 

 VOLCANIC ROCKS. 



Translation of a Lecture Delivered by M. Alphonse 

 Renard, LL.D., at the Royal Institution. 

 ( Concluded from p. \\%.) 



ACCORDING to Senarmont, one of the essential condi- 

 tions of a geological synthesis, is that each artificial 

 operation should be compatible with all the circumstances 

 where the natural operation has left characteristic traces. 

 The industrial slags and scoriae, whose relation to some of 

 the products of nature we have already discussed, are, in 

 reality syntheses, but syntheses of chance, which, in spite 

 of their great scientific interests, cannot be placed on the 

 same level as the intentional syntheses which we will 

 now examine, where the experimentalist, bearing in mind 

 the problem to be resolved, endeavours to realise, in his 

 laboratory, conditions identical with those which surround 

 the formation of the natural products which he wishes to 

 imitate. 



In the order of logic, synthetical methods follow to a 

 certain extent the progress of observation and analysis. 

 Nevertheless, it must be admitted that since the earliest 

 days of geology, a few master minds have, with the 

 glance of genius, discerned the light which later experi- 

 ence has brought to bear upon this science. Buffon 

 proved by experiments that granite and the principal 



