PHOSPJBO-NITROGENOUS MANUEES 247 



refuse, and from the carcasses of diseased animals of 

 all kinds. The fat, which is used as tallow, and 

 usually also a quantity of gelatine are removed by steam- 

 ing, and the residues are dried, ground up, and sold as 

 manure. The last-mentioned product is made chiefly in 

 Germany. A certain amount of bone is always included, 

 and it is therefore often called phosphatic meat guano 

 to distinguish it from the almost purely nitrogenous 

 variety obtained in the preparation of meat extract and 

 some other processes in which it is a bye-product. 



Nitrogenous samples contain from 10 to 13 per cent, 

 of nitrogen, and from 1 to 3 per cent, of phosphate. 

 The composition of phosphatic samples is more variable, 

 the proportions of bone and moisture being the chief 

 determining factors. They may contain from 10 to 20 

 per cent, of phosphates, and from 4 to 8 per cent, of 

 nitrogen, but all kinds of intermediate samples are met 

 with, from the most nitrogenous to the most phosphatic. 

 Even the last, it will be seen, is mainly a nitrogenous 

 manure. The phosphates and nitrogen are both insoluble, 

 but as the manure is usually in the form of a very fine 

 powder, and on open soils is fairly rapidly oxidised, they 

 soon become available to the plants. 



FISH GUANO. 



Fish guanos do not consist of the excrement of fishes, 

 but of dried fish offal, and are more properly described 

 as fish meals. They are produced at the fish curing 

 stations in this country, and are imported from abroad, 

 chiefly from Norway and America, in large quantities. 

 They are also made from surplus and decayed whole 

 fish, the carcasses of whales, etc., and are often called 

 herring guano, whale guano, etc., according to the kind 

 of animal from which they are chiefly prepared. As in 



