262 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVI. 



some plants grow in earth and others in water, so we find some bacteria 

 capable of growing in earth, and others capable of growing in the animal 

 body ; these latter are the pathogenic or disease-producing germs. Just 

 as you would not expect a " water lilly" to grow on dry earth, so you 

 cannot expect the pathogenic bacteria to find a suitable soil in the earth ; 

 or earth organisms a suitable soil in the animal body. I know of no 

 pathogenic organisms which have been proved to be capable of develop- 

 ment in earth ; and the plague bacillus is no exception to this rule. 

 You are familiar with the fact that plaDts can be reproduced either by 

 seeds or by cuttings. Bacteria multiply in the same way. Some bacteria 

 produce spores, which are practically seeds ; and others reproduce 

 themselves by a simple process of cleavage, — a portion is given off from 

 the parent bacterium, which is capable of reproducing itself, as a cut- 

 ting does. Now a seed can be kept for a long time in surroundings 

 which are unsuitable for its development, but when introduced into 

 suitable soil it buds forth and blossoms. It is precisely so with spore- 

 bearino - bacilli, they are capable of withstanding long periods of dessi- 

 cation, etc., and ultimately when introduced into suitable surroundings 

 they develop and multiply. Anthrax is a pathogenic, spore-bearing, 

 bacillus. By that I mean that its soil is the animal body, and it is able 

 on account of its spores or seeds to lie dormant in surroundings which 

 are unsuitable for its development — such surroundings as are found in 

 earth, on hides, and wool. Hence we find that anthrax in the cattle in 

 India can give rise, months afterwards, to anthrax in man in England. 

 The disease germs in the form of spores are transferred on the hides 

 and in the wool of the animals which have died of anthrax in India to 

 England, where among the workers in hides and wool the anthrax 

 spores, which have lain dormant during the voyage, may find suitable 

 soil when introduced into a cut or abrasion on the hand or other part of 

 a hide-worker or wool-sorter, producing anthrax in the unfortunate 



man. 



A^ain, we know that cuttings from some plants, for example the 

 rose, can be left exposed to air and light for some time, while cuttings 

 from other plants must be directly inserted into suitable soil after 

 removal from the parent plant. The resistance depends on the texture 

 of the plant, whether it has a hard protective covering, or only a thin 

 cuticle. Precisely so is it with bacteria ; some bacteria, which repro- 

 duce themselves only by fission (cuttings), can resist light and dessication 



