330 



Marvels of the Universe 



This statement may seem rather Irish, because, it will be seen later, Bacteria are cliaracterized 

 partly by their method of propagation, which is b}^ division. 



Bacteria have found that co-operation gives beneficial results ; hence, certain species seek partners 

 of honourable intentions. The partner chosen may be a higher plant, such as a tree, thus many 

 billions of times greater than the micro-organism. Or the matter mav be satisfactorily arranged 

 between Bacteria of different species. 



Bacteria are singularly fortunate in the rapid and easv method they have of reproducing their 

 species. This method is b^-- fission — that is to saj', each Bacillus divides into halves. The parts so 

 formed rapidly mature and divide again. Hence we have the astonishing theory that under optimum 

 conditions one bacillus may have the honour to be the ancestor of two hundred and eighty billions 

 of its kind in forty-eight hours. Under normal conditions, however, the multiplication is much 

 less rapid. From an experiment carried out a few years ago twenty-one Bacteria in three da3's 

 produced four hundred and ninety-five thousand — certainly a large family. 



They have also a further method which can 

 hardh' be considered reproduction. This is b\' 

 spores, in which form the organism is able to 

 remain dormant for lengthy periods. Spores are 

 egg-shaped, transparent bodies, singular for their 

 great resisting power, being able to retain their 

 vitality under the most adverse conditions. 



Although for years it was generally believed by 

 scientists that many diseases were caused b}? some 

 microscopic organism, it was not until a compara- 

 tively recent date that it was understood how these 

 organisms obtained their fell results. Many theories 

 were advanced, such as that the arteries of the 

 sufferer were congested with the personas of the 

 Bacteria. But to-day it is known that Bacteria are 

 able to produce a liquid, and that it is this liquid 

 which is responsible for the disease. Fortunately, 

 man, owing to an army of hard-working — but never 

 paid, nor usually even thought of — allies, is able to 

 protect his life against his would-be destroyers. 



To recapitulate. Bacteria are microscopic 

 plants ; their habitat is most varied ; they occur 

 in every conceivable position, and are tenants, welcome or unwelcome, even in the mouth and 

 alimentary tract of the higher animals. Some spend their lives in bitter antagonism to man and his 

 works, destrojdng all he produces, interfering with his domestic animals, his crops, and lastly, but 

 not of least importance, ruining his health and persistently attempting to destroy his hfe. Others 

 of a more friendl}' disposition, for reasons best known to themselves, help man directly and indirectly. 

 They render willing assistance in the production of some of his foods, such as cheese, butter, vinegar, 

 etc. Others help in the manufacture of his clothing — for e.xample, in the tanning of leather ; and 

 some, again, are of the greatest economical importance in the prevention of disease by destroying 

 refuse. This last characteristic has been utilized by man, and so to-day we have a bacteriological 

 method of sewage disposal, thus partly solving a most perple.xing and difficult question. It is 

 hardly necessary to mention that micro-organisms require food for their nutrition and for the pro- 

 duction of energy-, and are as dependent upon a food supply (except during the spore, or resting, 

 stage) as are the higher animals. Most of the flowering plants rely upon the atmosphei'e for their 

 carbon, which thej' obtain by means of the chlorophyll (green-coloured matter) present in their 



[Mnsrs. Uilz. 



I'lifilo I'ti /n-nnixxinti ^< '] 



TUBERCULOSIS. 



The germs of what has been called the White 

 Scourge, the consumption that destroys so many thou- 

 sands every year, is here shown inagnified about twelve 

 hundred times. 



