152 MADRAS FISHERIES BULLETIN [vOL. XI, 



and fed by the melting of the snow, etc., and by the drainage from 

 the fields. They lie nearly empty throughout the winter, so as to 

 kill off noxious animal life and useless vegetation. Once in every 

 ten years or oftener, the ponds are kept dry throughout the summer, 

 and cultivated with cereals (oats), which then produce a heavy 

 crop. This process sweetens the pond beds and destroys noxious 

 growths. It is usual to dig out during winter a quantity of the pond 

 mud, and this mixed with lime, is an admirable manure for the 

 arable land. The pond vegetation is, in general, natural, such as 

 " water roses " (lotuses and lilies), Vallisneria, Fcstuca ffidtans 

 (water rice), various sedges, etc. Shade in Germany is not gene- 

 rally desirable, for the one aim of the carp grower is to get and keep 

 the water as warm as possible during the summer. A very few 

 degrees of heat make a vast difference in the crop. Yet in parts of 

 Germany, as in France, it is found necessary to temper the extreme 

 heat which in shallow ponds sometimes raises the water almost to 

 blood heat, by properly selected and encouraged vegetation. This 

 not only shelters the fish but oxygenates and purifies the water and 

 the bed. In India owing to the great heat, external shade would pro- 

 bably be desirable while the droppings from the marginal trees 

 would provide useful food. The first farm visited comprised an 

 area of about l8o acres, of which half was shallow water, half 

 somewhat poor light sand. The homestead contained a neat house 

 and excellent farm buildings (everywhere in Germany one is struck 

 with the completeness of the latter), while the cow stable had about 

 a score of cows in splendid condition, as clean as washing could 

 make them, and floors of wood lightly covered with litter and 

 sloping gently to a central drain. The litter is daily removed with 

 solid excreta to the manure pit and fresh litter is put in; most of 

 the fluids, however, are intentionally drawn off by a central drain 

 through a pipe direct to the main pond of about 50 or 60 acres, in 

 order to assist in the growth of fish food. The merit of these 

 Bavarian carp growers is that they utilize land habitually covered 

 by water in the bottom of valleys too wet for ordinary cereal growth, 

 and that they assist the growth of the fish by manuring the water^ 

 just as they would manure the land, and occasionally by giving 

 small quantities of boiled or raw cereal food or domestic refuse. 

 The ponds are in general surrounded by and receive the drainage 

 from the cultivated lands, which whether pasture or arable, are all 

 manured; hence a considerable quantity of the manure is used 

 indirectly by the fish and not by the grass or cereal crops. All 



