MANUKES AND THEIE APPLICATION. 223 



does not contain all the necessary ingredients in tlie required 

 proportions to promote a strong healthy growth through the 

 Various stages and changing conditions of the life of the majo- 

 rity of plants. Analogy between the mode and means of 

 subsistence in the animal and vegetable kingdoms is generally 

 recognised. If the animal be supplied, according to its kind, 

 with nutritious digestible food, containing all the elements re- 

 quired for the formation of bone, muscle, and flesh, a good speci- 

 men should be the result. In like manner plants should have 

 within their reach at the proper time the proportions required 

 of the various elements which go to compose their structure, 

 and the formation of flower, fruit, and seed. Farmyard man- 

 ure being deficient in inorganic substances, such as potash 

 and lime, should not be given alone to root crops, especially 

 when the mineral elements have been withdrawn from the soil 

 by the frequent repetition of crops of the same nature. For 

 example, if potatoes were grown for several years in succession 

 in the same place, the crop would gradually become lighter and 

 inferior in quality. If this system were continued for any 

 length of time, although farmyard manure be abundantly sup- 

 plied, the ground would cease to bear from lack of sufficient 

 mineral to decompose the organic matter. By applying lime, 

 which has the power of liberating by chemical action the fer- 

 tilising properties in vegetable matter, and by returning to the 

 soil the other minerals removed by cropping, fertility is again 

 restored. On the other hand, if inorganic manures be applied 

 to such crops as brassica and pulse, and the soil be deficient in 

 humus, light crops will follow. The one class of manure is 

 entirely dependent upon the presence and action of the other for 

 the conversion of both into a suitable condition for absorption 

 and assimilation by plants, and it is evident that if the mate- 

 rials required for the construction, development, and matura- 

 tion of the plant are not present in sufficient quantities and 

 proportions, the growth will be slow and the parts imperfect. 

 It is, therefore, necessary to apply to the soil the elements in 

 which it is deficient by using artificial manures, most of which 

 are good when properly prepared and unadulterated, and have 

 proved a decided gain to the modern horticulturist. These 



