282 



SCIENTIFIC NEAA^S. 



[Mar. 23, i£ 



fore either encounter less resistance than the heterodro- 

 mous, or its electromotive force must be suddenly 

 strengthened, and that of the heterodromous current 

 weakened, by the sudden establishment in the tissue of 

 a new source of electromotive energy. The first is the 

 view taken by Professor du Bois-Reymond. 



The author, however, from his experiments is led to 

 assume that the phenomena of irreciprocal conduction 

 are in reality excitatory phenomena, the nature of which, 

 from the methods of investigation used, have not been 

 recognised. 



The second part deals with entirely novel phenomena, 

 namely, the excitation of the organ by the current of its 

 own excitatory state. It is shown that in vigorous 

 summer fish every response of the whole or part of the 

 organ to a single excitation of its nerves is followed by 

 a second response, due to the passage through its own 

 substance of the intense current of the first response. In 

 other words, the shock of the organ excites its own nerve 

 fibres and nerve endings, producing a feebler second 

 shock, which in a similar manner evolves a feebler third 

 shock ; this a fourth, and so on. 



The response of the isolated organ to nerve excitation 

 is thus multiple ; a primary, secondary, tertiary response 

 following the application to the nerve of a single stimulus. 

 Since all these responses produce currents similarly 

 directed through the columns of the organ, each column 

 during its activity must reinforce by its echoes the force 

 of the primary explosion, both in its own substance and 

 also in that of its neighbours. 



ROYAL INSTITUTION. 

 On March 8th the Rev. Dr. Dallinger, F.R.S., delivered 

 the first of a course of three lectures on the " Least and 

 Simplest Forms of Life." The lecturer, who is generally 

 known as one of the most eminent microscopists of the 

 age, drew in the outset a comparison between the pheno- 

 mena of the heavens, infinite in their vastness, and the 

 minute forms of organic life, almost infinitely small. In 

 describing these organisms, he mentioned that a hollow 

 cube, not greater in its dimensions than the diameter of 

 a human hair, could contain 100 millions of the largest 

 species of such beings. He showed the importance of 

 these micro-organisms in the economy of nature, since 

 without their agency the remains of dead animals and 

 plants would, under many circumstances, constitute a 

 mere encumbrance, instead of being, as now, made the 

 basis of new life. Whilst, however, putrefaction is 

 fermentation, a distinction was drawn between ordinary 

 fermentation and that saprophytic fermentation which we 

 commonly speak of as putrefaction. In the former kind 

 only one micro-organism is at work, and the ultimate 

 product is a definite organic compound. In the latter 

 the process is accomplished by a definite series of minute 

 organisms, which take up the task in succession, the 

 final result being the complete decomposition of the 

 organic matter, and its resolution into such single non- 

 organic substances as water and carbonic acid. In such 

 climates as occur between 50^ and 70" N.L. the work of 

 thus breaking up animal matter placed in water is 

 effected by ten species of microbia. The structure of 

 these organisms, as now ascertained by the use of the new 

 objectives made by the skill of Zeiss, working according 

 to the calculations of Professor Abbe, was compared with 

 that as seen even under the best microscopes in use five 

 years ago. Dr. Dallinger, on submitting some water 



which he had supposed was totally exhausted of all 

 putrescible matter for a few days at a temperature of 

 90" F., was surprised to find still two other kinds of 

 microbia, hitherto unknown, which seem to have the 

 especial duty of working up any remaining fragments of 

 organic matter. The lecturer had examined all these 

 minute beings and their functions from a purely biolo- 

 gical point of view, but he reminded his hearers that a 

 chemical study of the products successively generated by 

 these saprophytes remains to be undertaken, and that it 

 would doubtless throw important lights on sanitary 

 questions. 



ROYAL GEOGRAPHICAL SOCIETY. 

 On the 12th inst. Mr. Douglas W. Freshfield read a 

 paper on " The Peaks, Passes, and Glaciers of the 

 Caucasus." 



Mr. Freshfield gave an account of the results of a visit 

 he made to the Caucasus last summer, in company with 

 the well-known Hungarian geographer and Alpine 

 climber, M. de Dechy. Mr. Freshfield was one of the 

 early explorers of the Alpine portion of the Caucasus, 

 having visited it first more than twenty years ago. Mr. 

 Freshfield dealt mainly with that portion of the Caucasus 

 chain between Elbruz and Kazbek, the Central Caucasus. 

 That portion is 120 miles long, and from Naltshek to 

 Kutais 100 miles broad. With regard to the glaciers ot 

 the Caucasus, Mr. Freshfield stated that they are many, 

 and some of them are enormous. From imperfect 

 Russian surveys it is usually stated in the text-books that 

 the Caucasian glaciers are few and small ; Mr. Freshfield 

 showed that this is a complete mistake. Comparing the 

 Caucasus with the Alps, he maintained that the Central 

 Caucasus is much steeper than the Central Alps. The 

 Alps for purposes of discovery, Mr. Freshfield maintained, 

 are played out ; in the Caucasus there is a fresh field 

 not only for the mountain climber, but for lovers of grand 

 scenery, as well as for the naturalist, the geologist, and 

 ethnologist. Mr. Freshfield gave many details concern- 

 ing the populations of the Caucasus, about which many 

 erroneous notions still prevail. He described at some 

 length his ascent of Tetnuld, a peak considerably over 

 16,500ft. above the sea level. There was no great 

 difficultj"^, but the expedition was a very fine one. 

 Speaking of what he saw in his descent, from a height of 

 13,500ft., looking down on the great basin of the Bezingi 

 Glacier and the mighty peaks that encircled it, Mr. Fresh- 

 field said that the scene which burst on his view was ot 

 overpowering grandeur. 



BRADFORD NATURALISTS' SOCIETY. 

 At the meeting held on February 27th, Mr. B. Illing- 

 worth gave an interesting and instructive lecture on 

 " Life-histories of some of the Lepidoptera." Mr. 

 Illingworth confined his remarks to those species that 

 were the easiest to collect, beginning with the small 

 Tortoiseshell Butterfly Vanessa iirticce, a species common 

 throughout Britain. This insect passes the winter in 

 the perfect state, and pairing does not take place until 

 spring. After which the female deposits her eggs in 

 masses on leaves of the common nettle, and the young 

 caterpillars when hatched remain gregarious for some 

 time, after which they disperse over the whole bed of 

 nettles until full-fed, when they assume the chrysalis 

 condition, the perfect insect emerging towards the end 

 of June. The Peacock Butterfly V. lo. also feeds on 



