10 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



guide us to solutions to these questions, and it is by selecting 

 out the single forms, cultivating them in our microscopic garden 

 beds, watching their habits, and learning what they are about, 

 that we have succeeded in answering some of the questions 

 regarding a few of them. Some questions only, and regarding 

 a few of these minute beings only — I use these expressions 

 advisedly, for we are only at the beginning of the inquiry, now 

 actively going on in several quiet laboratories. 



The results already obtained are so startling and important, 

 that one wonders that the whole world of agriculturists, gar- 

 deners, and foresters, does not at once turn its attention to 

 stimulating further research into these new fields of practical 

 inquiry. 



In the first place we find a series of these organisms whose 

 whole life-functions are devoted to getting rid of the bits of stick, 

 dead leaves, and roots, pieces of paper and rag and other forms of 

 the substances known to chemists as cellulose and allied bodies, 

 converting them gradually into gases such as carbonic acid and 

 water, and so ridding the heavy-laden earth of a burden so 

 great that a very simple calculation shows that if they accumu- 

 lated unchecked there would soon be no room for man on this 

 planet. For it is quite a mistake to suppose that ordinary 

 plants can directly utilise these things. 



It has recently been shown that mud contains organisms 

 which, put under conditions as closely as possible resembling the 

 natural ones, will dissolve paper — and you remember paper is 

 only one form of cellulose or plant-fibre, and there can be no 

 doubt that these forms are active in every manure heap, sewage 

 Gum, marsh, refuse heap, and in cultivated soil. 



Another form has been separated and grown in microscopic 

 gardens, the function of which is to convert urea, which is 

 MoloflD to the higher plants, into certain salts of ammonia 

 which are or can easily be rendered very valuable to them, and 

 Without the co-operation of these organisms the urea put on to 

 land in stable-manure, sewage, and in other forms, would be of 

 no use to cultivators. 



A recent authority has calculated that, putting the number of 

 human beings at fifteen hundred millions, each excreting twenty- 

 tiv. -nuns of urea daily, there would be 37,500 tons of urea per 

 (ft in to be got rid of, or to accumulate. If we add to this the 



