monia. On this subject the following additional remarks 

 may perhaps be acceptable. 



The principle being admitted of the indispensable use of 

 ammonia to all kinds of crops, the question is then, How 

 does it act on vegetation ? 



When it is desired to increase the number of petals in a 

 flower, in other words, to transform a single into a double 

 flower, the experimenter chooses a single flower which shows 

 a few additional petals within its outer circumference ; the 

 appearance of these indicates an inclination of Nature to 

 deviate in this direction. This is then planted in a very 

 richly manured soil, where of course there is great abun- 

 dance of ammonia; with this treatment, each year, the 

 number of additional petals increases, until, after a series of 

 strong ammoniacal manurings, the whole interior area of the 

 circumference of the flower is filled with petals. But let it 

 be observed, that, in proportion as the number of petals in- 

 creases, the number of seeds decreases, so that in a full 

 double flower the seeds are generally obliterated. By re- 

 verse treatment, the seed-bearing power may be restored. 



This has been the course pursued by nature and art, and 

 this the result, with the well-known dahlia, within my own 

 knowledge, as I well remember its original introduction as 

 a single flower from Mexico, and have followed its succes- 

 sive transformations to the present period ; and this is the 

 process with the camellia, and all other double flowers. 

 The botanist very well understands that the additional petals 



