Lindley's Theory of Horticulhire. 161 



twelve years, I am forced to this conclusion, but I am very glad 

 the author lends the weight of his name in its favour. 



" We cannot reasonably doubt that a process so simple as that of dusting 

 the stigma of one plant with the pollen of another, which must be continually 

 happening in our gardens, either through the agency of insects or the currents 

 in the air, and which, where it takes place between two varieties allied to 

 each other, must necessarily produce a cross ; we cannot suppose, I say, that 

 this occurs in our crowded gardens and orchards at that time only when we 

 perform it artificially. The operation itself, although so simple, consisting in 

 nothing more than applying the pollen of one plant to the stigma of another, 

 nevertheless requires to be guarded by some precautions. In the first place, 

 it is requisite that the flower whose stigma is to be fertilised, should be de- 

 prived of its own anthers before they burst, otherwise the stigma will be self- 

 impregnated, and although superfoetation is not, by any means, impossible, yet 

 it is not very hkely to oc<;ur." 



This will be the means of turning the attention of many to 

 the subject, and the result will be the final settlement of the ques- 

 tion. If you think a short notice of my failures would be of 

 any use, I can send you the particulars. [We shall be vei-yglad 

 to receive them. Hybridising and cross breeding are the manu- 

 facturing of the raw material for human use.] 



In the practical portion of the work, or second book. Dr. 

 Lindley shows his intimate acquaintance with our art, by his 

 discrimination in selecting portions from the best authors in the 

 Hart. Trans., Gard. Mag., and other sources, to prove the 

 general principles of vegetable physiology. Every thing doubtful 

 he leaves as an " open question." Many useful tables are in- 

 troduced to prove how essential bottom heat is. The doctor is 

 quite a gardener on this point, and he makes it appear that Mr. 

 Knight was by no means against bottom heat; and that " the 

 dispute about bottom heat was not as to the necessity of it, but 

 as to the manner of obtaining it." 



The chapter on' atmospherical moisture and temperature is ex- 

 ceedingly interesting. This is the least-understood portion of 

 this part of the work : Daniell's instruments and writings, and 

 Mr. Thompson's tables and observations, are here brought into 

 full requisition. This chapter alone is worth the price of the 

 book. Many of the old gardeners will not say much in favour 

 of the next chapter, which is on ventilation. The three following 

 chapters are on seed-sowing, seed-saving, and seed-packing, and 

 ^re replete with useful information. The essence of the seed- 

 packing chapter ought to be sent out to all residents in foreign 

 climes who are in the habit of sending home seeds. Dr. Lindley 

 had previously published the greatest portion of this chapter, 

 and its details are well known and appreciated by scientific 

 collectors. The five following chapters treat on the different 

 modes of propagation. Propagation and amelioration are two 

 indispensable points in a gardener's education. The scientific 



