August 9, 1893] 



NA TURE 



;6i 



Its primary stratum has a depth of from 50 metres (Floyer and 

 jSeckenberger) to 100 metres (Zittel), and is horizontally 

 Ibedded between the Lower Londinian, a hard white limestone 

 of the Lower Eocene, and the Suessonian, a yellowish or greyish 

 limestone between the Lower Eocene and the Upper Cretaceous 

 iforraations." Prof. Mackenzie says that the substance is bard 

 ind stony in the deeper regions, and disintegrated near the 

 urface. The compositions of the samples obtained, however, 

 .0 not give any further information as to the possibility of 

 extracting the nitrate with any hope of commercial success, 

 "ifteen samples were sent to Prof. Mackenzie, and they con- 

 lained quantities of nitrate varying from i per cent, to 17-5 per 

 i:ent. The average of all would be equal to about 5 per cent. 

 >at whether this represents the composition of the mass, is open 

 o question. We understand that a lot of forty tons has been 

 aken to Cairo for extraction, and this will give a better idea as 



the possibility of success than can be obtained from the 

 inalyses of small samples taken at random from the surface. 



We recently referred to the important studies of >L Marcel 

 Jertrand on the geological structure of the Western Alp-. A 

 ull account of them, with maps and sections, has now been 

 ■ublished in the Bull. Sac. Gt'al. France. The author also 

 escribes the lustrous schists of that area, and concludes that 

 hey are a " flysch " facies of Triassic age. 



Ln a somewhat crude paper, entitled " Migration and the 

 ■ ' . 1 Quest, a Study in the Peopling of .\merica," contributed 

 1 1 lie American Anlhropolagisl ior ]\\\y, Mr. Otis Tufton Mason, 

 ;arting with the simple generalisation that the desire to appease 

 lUnger and thirst in the easiest way determines migration, seeks 

 vidence for the primitive peopling of America from the islands 

 f the Indian Ocean. The theory in its main features is 

 robably sound enough, but there are so few facts bearing on 

 ,ie application of the theory to the peopling of America, that 

 le specific question is not much advanced. 



I^K. F. Pleh.v, the German Government medical ofTicer in 

 le Cameroons, has made a special study of the beliefs and 



[jstoms of the Dualla negroes with respect to illness and death, 

 nd he has a paper on the subject in the last number of Danckcl- 



Jiana's Mittlieilungen aus den Deiitschen Schtitzgehieten. He 

 nds that, contrary to the custom of most primitive tribes, the 

 lagician and medical man have separate functions amongst 

 le Dualla. The magician lives in the bush, only 

 jming to the villages when his services are required, and his 

 uties are practically confined to the discovery of thieves and 

 f people who have used magic in order to produce illness or 

 eatb. The doctor may be a man or a woman, and the office 

 usually hereditary, although sometimes a student is initiated 



1 payment of a handsome fee. They have some knowledge 

 f the use of plant products as medicine, but are practically 

 i;norant of surgery. 



In the form of a lecture delivered at the Marine Biological 

 aboratory of Wood's Holl, .Massachusetts, Prof. J. M. Mac- 



j.rlane describes some very interesting observations on the 

 rito-contractility of plants. He maintains that, in the animal 



|i in the vegetable kingdom, we have to do with a true con- 

 aclile tissue. In the higher plants this tissue is made up of 

 .'lis, each consisting of an iriito-contractile protoplasmic sac 

 •closing a quantity of sap, each cell being joined to neigh- 

 auring cells by protoplasmic processes which pass through 

 iinule pores in the common cellulose membrane. Irrito-con- 

 actility may be started by stimuli of a mechanical, chemical, 

 lermal, luminous, or electrical nature. The seat of this con- 

 aclility is unquestionably the vacuolated protoplasm, and not 

 le cell-wall, as held by some observers. The degree of con- 

 action of an organ is proportional to the relative molecular 

 NO. 1293, VOL. 50] 



activity of the protoplasm, and to the strength or continuity of 

 the stimulus. Prof. Macfarlane has already shown that in the 

 leaves of Dion^ra contractility can only be excited by two succes- 

 sive stimuli separated by an interval of time ; and he now illus- 

 trates his conclusions by the phenomena presented by the closure 

 of the leaves in a number of different plants. 



The Report of the Director of the Aquarium of the U.S. 

 Fish Commission at the Chicago Exhibirion (Bull. U.S. Fish 

 Com. for 1S93, pp. 143-igo) is well worthy of perusal by those 

 who are concerned in the management of large aquaria, or 

 who take any general interest in such affairs. It is the record 

 of an ambitious enterprise, fraught with many inherent diffi- 

 culties ; and the frank statement which Prof. S. A. Forbes has 

 given, both of the failures and the successes which attended the 

 efforts of his staff", should be of considerable service in other 

 and future undertakings of a similar kind. The marine aquaria 

 had a capacity of 40,000 galls., and, although the necessary 

 supply of sea-water and marine animals had to be obtained at 

 a distance of nearly a thousand miles, this part of the exhibi- 

 tion gave the greatest satisfaction. The fresh-water aquaria, 

 paradoxically enough, were much more difficult to maintain in 

 good condition, owing to the ravages wrought among the 

 fishes by that well-known fungous pest Saprolcgnia, the germs 

 of which were found to be abundant in the water supply from 

 Lake Michigan. The precipitation of nocuous matter from 

 the water by the ingenious use of an alum tank, followed by 

 careful filtration, was the principal means by which the disease 

 was kept in check ; but the least derangement of the filtering 

 apparatus was immediately followed by a fresh outbreak of 

 the plague. Another equally troublesome pest made its appear- 

 ance during the hot weather in the form of an Infusorian para- 

 site {Ichlliyophthirius of Fouquet), which attacked and in- 

 flamed the skins of the less hardy fishes, and led to a great mor- 

 tality. "Young cat-fish died like sheep with the murrain." 

 Special observations on these two unbidden guests are given 

 as appendices to the Director's Report. It may be mentioned, 

 in passing, that Prof. Forbes speaks strongly in favour of the 

 employment of shallow open pools or basins, freely exposed 

 to sun and air, instead of the traditional deep narrow tanks 

 with sides of glass. 



K RECENT number of the British Medical Journal says 

 "that a large collection of indigenous medicinal plants and 

 drugs, fibres, and cereals has already been made in the Imperial 

 Institute from India and the East. A great many of the Indian 

 drugs have enjoyed a reputation in tropical diseases for the last 

 2000 years. They are, however, employed in the crude state, 

 gtnerally in combination with metallic and mineral compounds, 

 and do not therefore indicate their individual value as medi- 

 cines. They have, with a few exceptions, undergone no 

 chemical analysis or pharmacological experimentation, and such 

 researches have not yet been taken up either by Government or 

 by private individuals in India, neither are there facilities or 

 expert knowledge easily procurable for such researches. To 

 submit them to experts in London for proper investigation 

 would be very costly unuer the circumstances. The establish- 

 ment of a chemical and phaimacological laboratory in connec- 

 tion with the Imperial Institute, under a committee of experts, 

 would be a valuable addition. There are few institutions of 

 the kind where any original researches can be made in London ; 

 it will therefore be a very desirable and useful institution for 

 the promotion of science. It may in addition be expected to 

 help towards the discovery of important medicines and products 

 of great dietetic and commercial value. The benefits which 

 would accrue from the institution would be greatly appreciated 

 loth by English and Indian contributors to the funds of the 

 Imperial Institute ; and it would tend to bring together scien- 



