We have come to think that there can be no cleanliness without soap and water, and it may be necessary to remind the reader that the nomad Arab cleanses himself with the sand of the desert; that polished floors redolent of beeswax and turpentine are at least as wholesome as those that are scrubbed and have their crevices filled with a soapy slime; and that one of the best ways of washing a flannel shirt is said to be to hang it in the sun and beat it thoroughly with a stick. Necessity is the mother of invention, and were there a water-famine to-morrow, I have no doubt that those who were minded to be cleanly would somehow manage to be so.
There is no denying that dry methods of sanitation are in this country, where water is plentiful, far from popular. Dwellers in cities want to be rid of matters which have no value for them as individuals, and the luxury of having a scavenger 'laid on,' who can be set at work by merely turning a tap, and who, albeit that we pay handsomely for his services, does not hang about to be 'tipped,' are undeniable. Then, again, our scavenger is a very strict teetotaller and never strikes, although occasionally he is 'frozen out.' Many of us during a severe frost have, so to say, been the victims of dry methods and of 'water' closets, so called, on the principle of Lucus a non lucendo.
If dry methods of sanitation are to be successfully carried out, it is necessary to bear in mind the principles which underlie them.
Humification
The change which is produced in excrement when mixed with earth whereby the excrement is humified—i.e., changed to something which is indistinguishable by our senses from ordinary garden mould, or humus, is due to the action of fungoid organisms. Some of these belong to the 'mould' fungi, such as penicillium and saccharomyces, while others are allied to the schizomycetes, otherwise known as bacteria, bacilli, and micrococci.
A very important organism, or class of organisms, in this connection are those which bring about the nitrification of nitrogenous matters, whereby they are oxidised and made soluble, so as to be readily absorbed by the roots of growing plants. I prefer, however, to use the word humification in place of nitrification, because it is not likely that nitrification is the sole change which takes place, and it is at least highly probable that many of the fungi which grow in nitrogenous matter play a very important part in producing fertility and in feeding higher plants. The intestines of animals swarm with bacteria and allied bodies, and it may be assumed, in the absence of evidence to the contrary, that excrements carry with them, so to say, in the form of moulds and bacteria, bodies which help in their subsequent humification.
Which of us has not noticed the excrement of a dog, evenly covered with exquisitely graceful stalks of fungus as with a crop of erect white hairs. The greatest of all human observers must have seen this, for he makes the Queen say to Hamlet:
'Your bedded hair, like life in excrements,
Starts up and stands on end.'