68 Massee : The Action of Bacteria on Higher Plants. 



as elements or simpler compounds. Among-st such, as already 

 enumerated, are nitrogen and ammonia. Sulphuretted hydrogen 

 from stinking fish or rotten eggs, and the phosphorescence of 

 decaying fish on the beach also represent the work of Bacteria. 



What are popularly known as ' germs ' are Bacteria, but 

 respecting the numerous ills man and other animals are heir to 

 on account of their presence cannot be discussed here.'"' 



To give an idea as to the rapidity of reproduction practised 

 by the Bacteria, it may be stated that, in the comma bacillus or 

 cholera germ, the time occupied is twenty minutes ; hence it 

 follows that an individual of this species would during the cours.^ 

 of twenty-four hours under favourable conditions represent the 

 starting-point of a progeny of sixteen hundred trillions of 

 individuals, containing just over one hundred tons of solid 

 residue. 



This statement is perfectly correct, and nothing short of 

 Ignorance of the fact by the majority of people saves us from 

 an additional special thanksgiving that conditions are rarely 

 tavourable for the above indicated rate of growth of the 

 Bacterium. 



The opinion universally held, until quite recently, that when 

 manure is put in the gTound its gradual decomposition is 

 brought about by chemical and physical forces, until it is in 

 a condition available for plant food, is now known to be 

 incorrect, and is superseded by the proven fact that the 

 decomposition of manure is due to the action of Bacteria. 

 This statement is generally true, not only in the case of stable 

 manure or ' muck-middens,' but also as regards the breaking 

 up into an available form for plant food of such diverse sub- 

 stances as green crops when ploughed in, gas-lime, urine, and 

 -even the disintegration of rocks. 



The method by which manure and plant-remains generally 

 are rendered once more available for plant food by Bacteria 

 have been thoroughly investigated, and takes place as follows, 

 and illustrates a marked division of labour among these minute 

 organisms. 



'''' It is only necessary to briefly allude to the recent suggestion as to the 

 possible existence of a specific mycological germ, with which it is necessary 

 to be inoculated before a person can become a mycolog'ist or fung-us 

 man. The distinguishing- features of this g-erm are two — a marvellous power 

 of discrimination, not more than from twelve to twenty persons out of 

 forty millions proving- to be susceptible. Secondly, its extreme pertinacity, 

 one inoculation alone being- sufficient to make a person a mycologist for the 

 lerm of his natural life when efficiently effected. 



Natiir.-ilist.. 



