THE TESTING OF HUMOGEN 143 



A great variety of plants have been used for 

 experiments, Cotton, Tobacco, and Fuchsia being 

 among the numbers. In most instances the plants 

 grown in mixture No. 4 are so markedly superior to 

 those for which any other mixtures have been used 

 that the difference is apparent to the casual glance in 

 the increased size and improved healthiness of the 

 treated plants. Occasionally the complete fertilizer 

 mixture, a mixture containing every possible form of 

 food that a plant can require, has given as good 

 results, but this is exceptional. What is especially 

 noticeable at Kew Gardens is the increased root 

 development of the plants treated with the peat. 

 On taking the plants from the pots an abundance of 

 root is characteristic, there being a striking differ- 

 entiation in this respect between the plants grown 

 with peat and those grown with other soil mixtures. 

 Another feature, commonly noticed with variegated 

 plants, is the intensification of the variegation which 

 is comparable with that noticed in the colours of 

 the flowers. This has proved one of the unexpected 

 results of treatment with peat. Both foliage and 

 blooms are often richer in tone, the improvement in 

 foliage emphasizing and reinforcing that obtained 

 on the blooms. An increased sturdiness of the 

 stems may be regarded as being naturally connected 

 with the general symmetrical growth of the treated 

 plants, but in several instances it is strikingly 

 marked, notably at Kew in the case of the cotton 

 and tobacco plants. Generally, also, the plants are 

 larger and tend to mature earlier. 



While writing the present volume I took advantage 



