DISCOVERY 



121 



the friction skin of the lower monkeys are much simpler 

 in character. In the case of a ruminant animal, such 

 as the cow, it would be useless to look for any charac- 

 teristic patterns in the hoofs, but, acting on a sugges- 

 tion sent to me from America, I have made a number 

 of prints of cows' noses, and have found that the 

 arrangement of the sweat pores follows distinctive 

 patterns, which can therefore be used for the identifica- 

 tion of these animals. The two accompanying prints 

 (Figs. 7 and 8) were taken on December 22, 1922, from 

 the noses of two young Jersey heifers belonging to 



Figs. 7 ajid 



-XOSE-PRINTS OF TWO YOUXG JERSEY HEIFERS, 

 TAXEN DECEMBER 1922. 



Mr. E. Matthews, of Little Shardeloes, Amersham, and 

 may in future be of interest as the first prints of the 

 kind made in this country. It is obvious that the 

 patterns formed by the pores are quite distinct. The 

 practical value of this discovery lies in the fact that 

 it is not an uncommon practice for one cow to be 

 substituted for another and more valuable one after 

 the purchase has been completed. A registration of 

 the nose-prints of all pedigree animals would there- 

 fore prove an effective safeguard against this 

 fraud. 



At the request of the Committee of the Royal Agri- 

 cultural Society I am carrying out a further series of 

 experiments to determine whether the patterns are 

 permanent and remain constant in their form over a 

 long period in the growth of the animal, and whether 

 the differences are always as pronounced as in the case 

 of these two animals. 



It is quite possible that the same method of identifi- 

 cation could also be applied to dogs, and, if so, it 

 would be a very simple method of establishing their 

 pedigree. 



BIBLIOGRAPHY 



Locard, E., La Poroscopie. (A. Rey, Lyons, 1913.) 

 Mitchell, C. Ainsworth, Documents and their Scientific Examina- 

 tion. (C. Griffin & Co., London, 1922. Price 10s. 6d.) 

 Wilder, H. W., and Wentworth, B., Personal Identification. 

 (Richard G. Badger, Boston, U.S.A., igi8. Price $5.00 

 net.) 



The Artificial Feeding 

 of Crops 



By Sir E. J. Russell, D.Sc, F.R.S. 



Director 0/ the Rolhamsled Experimental Station 



Everyone is familiar with the idea of the feeding of 

 animals, but it is not so obvious that plants also need 

 adequate supplies of appropriate foodstuffs, without 

 which they cannot continue to live. Indeed, in spite 

 of man's long experience with growing plants, it was 

 not till 1S40 that any correct understanding of the 

 subject was obtained. Farmers had of course known 

 from the earliest days that farmyard manure was 

 beneficial to plant growth, and that certain crops such 

 as beans, lupins, etc., when dug or ploughed into the 

 ground, enriched it for succeeding crops. But the mode 

 of action and the effective substances were both un- 

 known, and there was no general body of scientific 

 knowledge to which an appeal might be made for help. 



The oldest hj^pothesis was that the black, sticky 

 substance in farmyard manure — the so-called "humus," 

 — constituted the food of plants : but it had not 

 universally been held, and at least two distinguished 

 seventeenth-century chemists — Glauber in German}', 

 and Mayow in England — had advanced evidence that 

 the nitrate formed during the decomposition of farm- 

 yard manure was the essential fertilising constituent. 

 The third hypothesis was advanced by Liebig in 1840 

 to the effect that the mineral constituents of the farm- 

 yard manure — the phosphates and the " alkali salts," 

 potassium, sodium, calcium, and magnesium — were the 

 true plant foods taken from the soil, all the remaining 

 plant requirements being drawn from the air. 



Lawes started pot experiments in 1839, but none 

 of these hypotheses fitted his results, which indicated 

 a strong need for nitrogen compounds as well as soluble 

 phosphates and " alkali salts." To put the matter to 

 a more serious test he and Gilbert laid out four plots 

 of ground receiving respectively no manure ; farmj^ard 

 manure; ashes of an equal amount of farmyard manure; 

 and these ashes -{- nitrogen compounds (ammonium 

 sulphate). The results were as follows : 



Produce of Wheat per Acre, 

 rothajisted. 



No manure .... 



Farmyard manure (14 tons per acre) 

 .\shes of 14 tons of farmyard manure 

 Ash constituents -f- nitrogen compounds 



(ammonium sulphate) up to . . . 26J 1.772 



The e.xperiment showed then that farmyard manure 

 owes its value, not, as was for long supposed, to the 



