THE ROCK OF THE LUMBWA CAVES 
487 
there does not appear to be anything in the material itself 
which is of value in the direction of supplying elements re- 
quired in animal metabolism ; it may be that its function is 
that of an anti-acid — i.e., that the animals eat to neutralise 
excessive acidity of the gastric juice. 
An experiment was made to ascertain the power of the 
material to neutralise a solution of hydrochloric acid of a 
similar strength to that occurring in the stomach of stock. 
One hundred grams of finely powdered material (the 
sample whose full analysis is given above) were digested with a 
litre of 0*3 per cent, hydrochloric acid for twenty-four hours, 
and then filtered. The filtered solution contained 0*9 per 
cent, solid matter, showing that dilute acids have considerable 
solvent action on the material. Under the conditions of the 
experiment, the acid was largely neutralised by the mineral 
— about 90 per cent, disappearing. 
A physiological experiment is necessary to ascertain the 
precise function of this rock. It may be useful, by mechanical 
irritation of the bowels, in regulating their action or dis- 
couraging intestinal parasites. 
THE SOUTH-EAST FACE OF MOUNT KENYA 
By Capt. G. St. J. Orde Brown, R.A. 
Extracted from the * Geographical Journal ,’ June 1918 
Such exploration as has already been done upon Mount 
Kenya appears to have been largely confined to the northern 
and western aspect of the mountain. Mackinder and Gregory 
both attacked it from those sides, while the more recent 
Roosevelt Expedition also largely neglected the south-east 
slope. The following notes are made without claim to scientific 
value, but in hope that they may be of use to subsequent 
explorers wishing to investigate the least-known side of this 
very interesting mountain. 
The characteristics of the south-east aspect may be summed 
