No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 193 



is small as compared with that supplied by X, since the N in the fish will 

 produce only little more than one-fifth, and the PA two-fifths, of the grain 

 producible by those elements respectively as contained in X. But the 

 value of a fish fertilizer to the agriculture of a country is well displayed 

 by the use to which it is put in Japan. Its value and the comparatively 

 moderate amount yet in use and the diminishing quantity annually 

 available, explain in part the anxiety of the Japanese Government to 

 develop its deep sea fisheries ; it is all very good to take in herring 

 and sardine when they arrive at the door, but far larger supplies are 

 needed for which it is sought to promote the use of much larger boats not 

 only to seek and follow the shoals when found (as in the case of 

 menhaden, etc., on the American Coasts) but to go to distant shores and 

 seas (Korea, China, Saghalien, Russia, etc.), where fish are to be found 

 in vast quantities. If this is the need in Japan with already 134,000 tons 

 of fish fertiliser in use on good soils, the lesson for Madras is obvious. 



(105) Fish is not generally used by itself (except, it is said, for 

 indigo) but in conjunction with other manures, chiefly compost ; it is a 

 favourite manure on the tea plantations, which, in Japan, form part of the 

 peasant farmer's ordinary cultivation on the plains ; this shrub is said to 

 be manured four times annually, the heaviest dose being given in spring; 

 oil-cake and fish are said to be particularly effective, but in their absence 

 and for the oldest plants, X is much in use. The dry fish scrap is 

 pounded and mixed with fine compost for general use. 



'(106) Dr. S. Nagai mentions the preparation and use of a lixivium 

 prepared from fish refuse as mentioned above, end of paragraph 102. 

 The heads, guts, skin, bones, etc., of large fish such as the tunny, are 

 collected from the fish dealers or from the restaurants and sent up country. 

 The purchaser puts them into a vat, pours over them the hot bath water 

 from the house (the Japanese bathe "daily in very hot water), and repeated- 

 ly stirs up the mass, which is then covered up with straw mats and left to 

 the putrefactive fermentation which rapidly sets in. After some weeks the 

 putrified and partly liquid mass becomes of a dark greenish colour with a 

 smell almost insupportable ; the liquid part is removed and largely diluted 

 when used ; the undissolved residue is used with fresh matter for a new 

 brew. It is said to cause a very rapid development of the plants to which 

 it is applied. 



The diagram for manures in the paddy field is here reproduced 

 and shows at a glance the respective gross produce and the net profits 

 obtained by the use of eight different mixtures, the gross return being 

 marked by the red lines and the net profits by black ; for instance, it will 



