514 



NA TURE 



[March 29, 1894 



Koch and Kossowitsch's experiments, make it impossible to 

 deny that the above hypothesis as to the powers of the proto- 

 plasmic machinery may apply to the cells of some lower organ- 

 isms, without symbiosis coming into play at all. The 

 remarkable facts brought to light regarding sulphur-bacteria and 

 iron-bacteria by Winogradsky, and the still more unexpected 

 results this observer obtained with nitrifying organisms, show 

 that the machinery of the cell can avail itself of sources of energy 

 undreamt of by earlier observers. If, by the oxidation of 

 sulphur or sulphuretted hydrogen, or of lower iron-compounds, or 

 of ammonia, certain of these organisms can obtain the energy 

 necessary to set going machinery capable of so presenting other 

 molecules of the elements they take up to one another that 

 organic compounds result, it is by no means inconceivable that, 

 at the cost of carbon-compounds which they oxidise powerfully, 

 the necessary energy can be obtained to force even free 

 nitrogen into combinations. 



It is equally conceivable that in the case of the leguminosae, 

 the symbiotic organism is really more of a parasite (it is neces- 

 sarily a parasite in some degree) than is assumed in the third 

 view, and that, at the expense of the carbo-hydrates so richly 

 furnished to it by the host plant, the fungoid organism alone 

 supplies the machinery for forcing the nitrogen into combina- 

 tion, and that when it has stored up relatively large quantities, 

 owing to its activity in the incubators — the root-nodules — pro- 

 vided for it by its host-plant, and is diminishing in resisting 

 power, the latter at length turns round and absorbs the 

 stores. 



The chief objection to this view is that the gains in total 

 nitrogen seem to be greater than would be thus explained, 

 unless the organisms in the soil outside the roots are also fixing 

 free nitrogen. 



Such then, put too shortly as regards the numerous experi- 

 mental facts, are some of the chief ideas agitating the scientific 

 world on this question, a question which, be it emphatically 

 stated, promises to be of more importance to agriculture in the 

 future than any legislation as to prices, &c. that we can conceive ; 

 for if it turns out that the acquisition of free nitrogen by the 

 land, or, what amounts to the same thing, the plants growing 

 on it, can be economically promoted, the farmer and forester 

 may have the control of sources of real wealth not yet dreamt 

 of. Unquestionably there is an enormous amount of careful and 

 very difiicult experimental work to be done before we arrive at 

 the solution of the various vital questions raised ; but the as- 

 tounding results obtained during the last decade by a few earnest 

 workers promise brilliant results in the future. 



H. Marshall Ward. 



THE HAR DALAM CA VERN AND ITS 

 OSSIFEROUS CONTENTS. 



TT is now about half a century since Admiral Spratt first 

 recorded the discovery of the Maltese ossiferous cavern de- 

 posits in which, at a later period, Prof. Leith Adams found so 

 remarkable an assemblage of mammalian and other remains. 



The fauna which was then brought to light was of a most 

 unique and interesting character, consisting of three species of 

 elephants, one of which E. falcone7-i was, when full grown, no 

 larger than an average size Newfoundland dog ; two species of 

 hippopotamus, one H. minutns, about the size of a small 

 donkey, several species of gigantic swans, large dormice, land 

 tortoises, cranes, vultures, &c. 



These remarkable discoveries in an area so circumscribed at- 

 tracted much attention in the scientific world, and considerable 

 interest was evinced in them ; and this the more so as that Dr. 

 Falconer was at that time engaged in determining certain organic 

 remains which had been found in similar deposits, and under 

 similar conditions, in Sicily. The result of the explorations in 

 the two islands was to demonstrate that Malta had, at no very 

 remote period, been directly in connection with the continental 

 areas on the European side, and indirectly with those of Africa. 

 Brilliant, however, as were the discoveries made by Spratt and 

 Adams, many difficulties of vital interest to the archaeologist, the 

 geologist, and the physical geographer were left unsolved when 

 Adams departed from these islands in 1872. Dr. Caruana, a 

 Maltese archaeologist, then carried on the work for a short time, 

 but finally abandoned it ; and from that time to the arrival of 

 Dr. John Murray, in 18S9, nothing further was done. In that 



NO. 1274. VOL. 49] 



and the following year. Dr. Murray undertook a thorough in- 

 vestigation into the marine strata of the islands, and recognising, 

 the value of the work that still remained to be done in the Pleis- 

 tocene beds, he urged the desirability of a careful examination 

 of them being made. Several interesting discoveries of Pleisto- 

 cene deposits had already been made by ]\Ir. John H. Cooke, in 

 the island of Gozo ; and accordingly, at the suggestion of Dr. 

 John Murray, and with the assistance of the Royal Society, Mr. 

 Cooke undertook to carry on the work. 



In the spring of 1892 the excavation of a large cavern situate 

 in the Har Dalam Gorge was commenced, the results of which 

 have materially assisted in clearing up many of the more debat- 

 able problems which had been left unsolved by previous workers. 

 These results have been embodied, by Mr. Cooke, in a memoir 

 which was communicated to the Royal Society. 



The gorge in question is one of many gorges of erosion, which 

 are to be found in the low-lying and denuded areas of Malta and 

 Gozo. It is situated in the eastern part of Malta, and debouches 

 on the broad, extensive bay of Marsa Scirocco. It forms the 

 drainage channel of a catchment basin of considerable area, but 

 owing to the very small annual rainfall of the islands the stream 

 that now courses through it for a few occasional hours in the 

 winter season is insignificant in size, and impotent as an eroding 

 agent. 



But it was not always so. The rounded boulders, the water- 

 worm debris, and the curvilinear undercuttings with which the 

 sides of the gorge are scored, as well as the character of the caves 

 in the vicinity and of their deposits, all attest to the former action 

 of torrential volumes of water such as could only have been 

 formed during the existence of climatic conditions of a much 

 more severe and humid nature than those that now endure. The 

 cavern, which has been named after the gorge in which it occurs, 

 is situated 500 yards from the shore on the northern side of the 

 gorge, and consists of a main gallery, 400 feet in length, when 

 it ramifies in various directions, forming smaller tunnels and 

 chambers, which follow the jointings and bedding planes of the 

 rock. One branch fissure is 250 feet in length, 15 feet high, and 

 just wide enough for a man to pass along it, widening out at 

 intervals into dome-shaped rock chambers. 



Two of the other galleries are of considerable height, but do 

 not exceed 20 feet in length ; and they were filled with debris to 

 within I ft. 6 in. to 2 ft. of the roof with a reddish plastic clay, 

 kept moist by percolation from the roof, the sides of all the gal- 

 leries being encrusted with a stalactitic lining. 



The mouth of the main gallery is 26 feet wide and 10 feet 

 high, and has been used during late years as a cattle shelter, the 

 entrance being walled up and provided with a doorway. It 

 widens inwards into a spacious chamber, 60 feet wide and 17 feet 

 high, having a branch on the right hand, which was filled to the 

 roof with alluvial soil and boulders. 



The roof of the cavern was formerly covered with stalactites, 

 but most of them have been broken off by the action of the tor- 

 rents that invaded the cave, and they were afterwards buried in 

 the floor deposits. 



These stalactites and their corresponding stalagmitic bosses 

 were observed at three different levels, each being covered by 

 fresh alluvial deposits, indicating the intermittent character of 

 the floods that invaded the cavern and the long periods that 

 elapsed between them. 



The deposits met with vary considerably in different parts of 

 the cave. At the furthest extremity they are mainly composed 

 of red loam ; in the middle of large boulders, broken stalactites,, 

 and old pottery enclosed in clay ; towards the entrance of a grey 

 indurated marl with abundant remains of land shells, roots of 

 plants, bones of deer, and boulders. 



The cave is everywhere strewn with enormous quantities of 

 waterworn boulders, similar to those met with so abundantly 

 in the valleys and gorges of the islands. 



From the differential characters exhibited by the earlier and 

 later layers, it was evident that the deposits belonged to two 

 distinct epochs, each of which was characterised by a special 

 fauna. 



In the lower series were found the remains of Ursits {arcioi?), 

 Elephas mnadransis, Hippopota7ni fcntlandi, Canis (equaUing 

 a wolf in size), Cerinis ciaphiis, var. harharus, and Human 

 remains ; while the upper series was found to abound in the re- 

 mains of man and domestic animals — pig, goat, sheep, Ifos, 

 small land chelonian, and-Cc'rvus elephus, var. barbarus. 



The discovery of the carnivorae was specially significant. As- 

 early as 1859 Spratt had observed that many of the bones that 



