March 7, 1878] 



NATURE 



369 



oxidising the nitrogen of organic matter and of ammonia, 

 and thus producing nitric acid. 



The organisms which produce these wonderful changes 

 consist of colourless cells ; they are independent of day- 

 light, for they derive their supply of carbon exclusively 

 from organised matter, and from the decomposition of 

 such matter they obtain the force necessary for life and 

 growth. In these respects they differ entirely from green 

 vegetation, in which sunlight is the source of all energy, 

 and carbonic acid gas, decomposed by the aid of light, 

 the material from which carbon is derived. The colour- 

 less and green organisms, however, equally require 

 phosphoric acid, potash, and other ash constituents ; and 

 both appear to be capable of assimilating nitrogen in the 

 form of ammonia. 



Not only are these simple organisms independent of 

 the aid of light, but light is, in some cases at least, actually 

 fatal to their existence. This fact has quite recently been 

 established by Downes and Blunt. They find that the 

 bacteria present in an organic fluid may in many cases 

 be entirely destroyed by exposure of the solution to day- 

 light, and that even when this is not the case, their 

 development is much retarded by such treatment. This 

 observation is perfectly in accordance with the fact ob- 

 served at Rothamsted, that nitrification did not proceed 

 in solutions exposed to daylight. In the last communica- 

 tion of Schloesing and Miintz, it is stated that vegetable 

 soil suspended in water by passing a stream of air through 

 the mixture, undergoes nitrification both in light and 

 darkness. No details of the experiment are given, but it 

 seems probable that such a mixture would be more or 

 less opaque, and the greater bulk of the material conse- 

 quently at all times in partial darkness. 



The microscopic organism producing nitrification has 

 probably distinctive characters, and might be isolated by 

 cultivation under conditions specially suitable to its 

 growth, but more or less unfavourable to the life of other 

 associated germs. Pasteur has pursued this method with 

 success in the case of beer yeast, and has shown that with 

 the pure yeast thus obtained an unchangeable beer may 

 be manufactured, the organisms producing secondary 

 changes having been excluded. The subject of nitrifica- 

 tion has clearly reached a stage which demands the aid 

 of the vegetable physiologist. R. Warington 



FOSSIL HUNTING AT BOURNEMOUTH 



I HAVE recently deposited in the South Kensington 

 Museum some unusually large specimens of fossil 

 plant remains from Bournemouth and Studland. The 

 matrix in which these are imbedded is friable, and the re- 

 mains, in most cases, are extremely difficult to extract, 

 so that a brief account of the process employed may be 

 of use to would-be collectors. The largest specimen, 

 part of the frond of a feather-palm, measures 4 ft. by 

 3 ft., and as this presented the greatest difficulties, I will 

 more particularly describe the work which its preservation 

 involved. 



In digging last autumn at Bournemouth in a bed of 

 dark clay about 60 feet above the sea- level, and about the 

 same distance from the top of the cliff, we came across a 

 well-preserved fragment of this specimen consisting of a 

 portion of the stem with the bases of pinnae attached. 

 We included a younger athletic brother, a coast-guards- 

 man whom I have long employed, as well as myself, 

 and occasional other assistance. The tools we used 

 were pick-axes, crow-bar, and spades. The place was 

 a slightly projecting ledge, none too solid, with a steep 

 cliff above and below. So soon as the fragment men- 

 tioned was brought to light by a stroke of the pick digging 

 was stopped, and a careful examination was made by the 

 aid of our knives to see in which direction the frond 

 trended. Finding, fortunately, that the direction was 

 towards the mass of the cliff, we determined to use our 



endeavours to extract it in as perfect a condition as 

 might be. We therefore, at about mid-day, commenced 

 to dig away the superincumbent mass until a slab was 

 bared at least twice the size of that ultimately required, 

 when we proceeded to clear down and lay bare the 

 specimen. Loose sand blowing up in clouds, how- 

 ever, settled upon it and threatened to adhere so 

 firmly to the wet clay that it was feared it might be 

 found impossible to remove it, whilst the drying action 

 of the wind caused it to crack and peel, notwith- 

 standing all our efforts to keep it covered with damp 

 paper and linen. It was then determined to remove the 

 slab without exposing the leaf, leaving that operation 

 until it was safely housed at home, and we therefore com- 

 menced the laborious operation of undermining this great 

 slab and removing it in such pieces as from time to time 

 broke away by their own weight from the main mass. 

 For five hours these pieces kept breaking away in blocks 

 of about one foot in thickness, and as much in weight as 

 two or three of us could lift. At dusk our task was not 

 more than two-thirds completed, but as wet was expected, 

 it was determined to extract the whole that night if possible. 

 Perhaps the most toilsome part of the work was carrying 

 the pieces up the sixty feet of cliff. A hand-barrow having 

 been improvised, it required our united efforts to convey 

 each piece to the path above, and this was really hard 

 work, and in addition I had great anxiety throughout lest 

 the edges should be rubbed. Notwithstanding all our 

 trouble we had the mortification of seeing our large lumps 

 repeatedly break and subdivide. The work went on until 

 about 9 P.M., when we found it impossible to continue, 

 and therefore carefully covered up the remains of the 

 slab, the vicinity of a populous town rendering this pre- 

 caution necessary. The next day the whole of the 

 pieces were removed in a cart from the coast-guards 

 station to an out-house in our occupation. When they 

 arrived there the prospect was far from hopeful. We 

 had apparently but a truckful of lumps of black wet- 

 clay, a foot or more in thickness, and varying in dia- 

 meter from a few inches to two or three feet, the 

 majority without trace of the fossil upon them, or any 

 marks or indication of how they were to be fitted to- 

 gether. Experience among these fossils has taught me 

 not easily to despair, and I knew, moreover, from the 

 care that had been taken, that the edges could not be much 

 abraded, nor could any considerable pieces be missing. 

 Our lodging contained a new and comparatively well-lit 

 cellar, to which all was removed. A table was next made, 

 six feet long and four feet wide, and portions of three 

 days occupied in ascertaining how the pieces could be 

 fitted together. 



Two days were then lost in fastening the smaller pieces 

 together into larger slabs, but it was found that these 

 larger pieces would not come together properly in the 

 box, their relative thickness, &c., being different. They 

 were next reduced in thickness to about three inches 

 and transferred to the box in which they now are, and 

 fitted together as accurately as possible and fixed by glue 

 and plaster of Paris, \ cwt. of the latter being used. 



A great disappointment now awaited us. From stand- 

 ing and kneeling upon the slab whilst engaged in digging 

 it out, the upper surface of the leaf was kneaded into 

 the under surface, and would not part for weeks after- 

 wards, until quite dry, and then in very small fragments 

 only. 



Another difficulty was that two other fronds were found 

 at lower levels traversing the one we were endeavouring to 

 save, and in some places these had been cleaned out before 

 the mistake was discovered. The base of the frond, it 

 will be seen, has been abandoned altogether, and not 

 more than two-thirds is now preserved. The next thing 

 was to get it to London safely, and the railway officials 

 were cautioned as to the care required and the necessity 

 of keeping it flat and right side up, and the case . was 



