396 By ei, SANTIGHING 
bring about the rapid and abnormal proliferation of the tissue cells. 
These growth stimulants have been termed auwzetics, and it is not im- 
probable that they resemble in their action, if not in their chemical 
constitution, the vitamines which cure the disease of beri-beri and the 
potent substance occurring in natural sea-water, the merest trace of which 
is capable of producing a luxuriant growth of diatoms in an artificial solu- 
tion, which in its absence is unable to sustain growth at all. 
A still closer parallel to what occurs in the case of the diatom cultures 
has recently been brought to light in connection with agricultural re- 
search. I refer to the investigations of Prof. Bottomley, of King’s 
College, London, on certain substances derived from Sphagnum peat. 
Sphagnum peat consists of the partly decayed remains of the Sphagnum 
moss, which occurs so commonly in moorland bogs, as for example in 
much of the bogland of Dartmoor. Prof. Bottomley found that when 
Sphagnum peat was subjected to the action of certain bacteria obtained 
from soil, a kind of fermentation took place which resulted in the forma- 
tion of a substance which, when fed to growing plants, stimulated and 
accelerated their growth to a quite surprising extent. This substance 
was soluble in water and was effective in very small quantities. Prof. 
Bottomley states that “‘ Dr. Rosenheim, of King’s College, found that 
seedlings of Primula malacoides potted up in loam, leaf-mould and sand, 
and treated twice with a water extract of only two-tenths (0-18 grams) 
of a gram of bacterised peat, were after six weeks’ growth, double the 
size of similar untreated plants, and it was noted that flower production 
and root development were promoted equally with increase of foliage.” 
By using methods similar to those which had been employed in separ- 
ating vitamine from rice polishings, Bottomley was able to separate 
the active substance from the bacterised peat and to test its effect upon 
the growth of wheat seedlings. Some seedlings were allowed to grow 
in a solution containing only pure food salts (nitrates, phosphates, and 
so on), whilst others were grown in the same solution to which one part 
in three millions of the active substance from bacterised peat had been 
added. During the first fortnight both sets of seedlings grew at about 
the same pace. After that those to which no active substance had been 
fed began to dwindle, and at the end of fifty days their weight had 
actually diminished by 8-4 per cent. Those seedlings, on the other hand, 
which had received the one part in three millions of active substance 
from the bacterised peat, continued to grow and at the end of the fifty 
days their weight had increased by 55 per cent of the original weight. 
Bottomley’s observations are of great practical interest, since they 
seem to explain in an intelligible way the beneficial effect upon crops 
of farmyard and organic manures. It is not sufficient to add to the soil 
