HOW THEY MULTIPLY. Orgatnisms have to be surrounded with special conditions to propagate, such as suitable temperature, food, and moisture; and given these it is wonderful lo learn of the rapid man ner in which these cells or germs multiply. The rod-shaped cell or bacillus reproduces its kind. It grows rapidly and on attaining adult, size it multiplies in a most simple manner by dividing in th/: middle into two equal parts each of which becomes a distinct cell. Thus we have two cells from one parent cell. This process known as fission, progresses, and with suitable con dihuus for growth goes on till the food is exhausted or they surround themselves with the waste products of their own bodies, and this checks the increase. A lod has been known to divide in lmli'-an-hour. At this rate of increase one cell or germ in 24 hours will become 17,00(1.0(10. Other forms or varieties propagate by means of spores or seeds. All germs must have food to build up their own bodies; digeslive changes take place, and I hey excrete or throw off certain chemical substances | They are engaged in efTec-lini; dis : tincl changes, and a knowledge of .these renders their application lo ' industrial processes of immense ! value.
