Makgill. — Nature's Efforts at Sanitation. 141 



Organic Waste. 



There is a well-known saying that there is no waste in 

 nature, and the truth of this is most strikingly observable in the 

 constant circulation of organic matter. The relationship be- 

 tween animal and vegetable life is a simple illustration, the 

 animal building up its body by means of the grass it eats, 

 which building process is accompanied by a breaking-down or 

 combustion, shown by the exhalations of carbonic acid and 

 water in the breath, waste products of the vital process. The 

 green leaves of plants absorb the carbonic acid, using the 

 carbon and giving off the oxygen to aid in the further com- 

 bustion, while the water is deposited as dew, to be absorbed 

 by the rootlets. The plant utilises the waste products of 

 animal life, and, building them up, furnishes a fresh supply of 

 food. 



The most interesting point is the circulation of nitrogen — 

 the most important element in organic matter — for by follow- 

 ing this up we learn about Nature's scavenging process, by 

 which organic waste material is not only disposed of but 

 re-utilised. Organic matter is a complex body, built up by 

 vital processes of the elements, carbon, oxygen, hydrogen, 

 nitrogen, and sulphur. These elements are too valuable to 

 waste, and therefore when a plant or animal is dead the mass 

 of organic matter becomes a potentiality for further life. But 

 Nature does not seize on the dead body and hustle it down a 

 sewer, to be deposited on the sea-beach, nor does she bury it 

 in a hole so deep that it is not available for any purpose. 

 Instead, the body lies on the surface of the ground, and an 

 army of sanitary officials at once set to work to make use of 

 the stored material. And things are so balanced that each, 

 while unconsciously working out the general scheme for dis- 

 posal and utilisation, is at the same time making his own 

 livelihood in the process. The first of the scavenging party to 

 appear is familiar and objectionable — the blow-fly and house- 

 fly. They come to feed and lay their eggs, so that the 

 young, when hatched, will be assured of a plentiful supply of 

 food. It may be objected that the fly is a weak point in 

 Nature's scheme, as it is certain it can carry infection from 

 diseased matter. But in that scheme it is not intended that 

 decaying matter be smeared round our dwellings, so giving the 

 fly a chance to spread disease. Our sense of smell may be 

 regarded as a sanitary precaution, warning us to avoid the 

 close proximity of offensive things, just as it doubtless serves 

 to guide the fly to his special form of food. As decomposi- 

 tion advances another set of scavengers appear — namely, 

 varieties of beetles, who live on the fatty matters. The well- 

 known burying beetle is a specially energetic member of this 



