146 ^^- SCIILEIDEN'S TIIKORY OF AGHrCULTUEE. 



local causes ; but, from the facts wliioli may be gleaned from an 

 investigation of the subject, theie c<in be no question that many 

 plants, which in various localities are spring-tender, might be 

 rendered otherwise in the same districts. Many which occupy 

 warm, sunny situations, open to the southern aspect, sliould have 

 been removed from the influence of the early sun altogether, 

 especially in their young state. It is not to much the action of 

 the frost alone on vegetable life that causes injury, as the rapid 

 reaction of the frozen parts by the stimulating influence of the 

 sunbeams. A frozen vegetable, allowed to thaw gradually in a 

 suppressed light, may escape uninjured, while one submitted to 

 the same intensity of cold, and then in that state brought into a 

 bright light and corresponding warmth, will wholly perish. The 

 animal economy presents corresponding phenomena. 



That plants may be, and very often are, " killed with kind- 

 ness," to use a homely phrase, tliere can be no doubt. Such as 

 are known to be tender are often, without attempting to ascertain 

 the kind of tenderness which they exliibit, placed in the warmest 

 and most favourable position. Such Avould of course in many 

 instances be advisable, in others destruction to the plant would 

 follow. Discrimination must be exercised. A little wholesome 

 severity is often found as useful to a plant as to an animal when 

 its future career is taken into considei'ation, and forms an object 

 of solicitude. 



This subject might be much enlarged upon : other points for 

 discussion I shall defer till some future opportunity. 



X.' — Dr. Schleiden^s Theory of Agriculture. By the Rev. 

 M. J. Berkeley, M.A., F.L.S. 



[Continued from p. 46.] 



In considering the objects of cultivation two opposite questions 

 arise for our solution — the one theoretic and the other practical. 

 The first is how to attain with every special exertion no more 

 than one single end and to act upon one condition only of vege- 

 table life. In so doing we should be in a j^osition to measure 

 exactly the degree of that exertion, and consequently to bring 

 it into perfect unison with the end to be effected. This ideal 

 perfection may and should be our aim in every trial and experi- 

 ment, and the more we advance towards it the surer shall Ave be 

 of a useful result. 



The other is the practical. The object here is to supply the 

 wants of man as abundantly and at as cheap a rate as possible, 



