34 FUNDAMENTAL PROPERTIES 



goes on to say {loc. cil. p. 47) :— " The integrity of this principle 

 has now been destroyed by the discovery of certain bacteria in the 

 soil, which are able, even without sunlight, to appropriate the 

 carbon dioxide of the atmosphere." These are the nitrifying 

 bacteria, present in every variety of soil, which were first isolated 

 in 1889 by a Russian investigator Winogradsky, and are " character- 

 ised by an extremely primitive metabolism, a physiological humility 

 which shows them to occupy the very lowest rung of the ladder of 

 life." 



But the fact recorded by the writer in 1871 that Bacteria were 

 capable of multiplying freely in a simple solution of ammonic 

 tartrate in distilled water as mentioned in the last chapter (p. 18) 

 showed that other common Bacteria and some Torulas possessed 

 closely allied properties, of an even simpler order. Speaking of 

 the nitrifying Bacteria Fischer says, "The materials from which 

 they build up their cells are therefore inorganic compounds of the 

 very simplest character, carbon dioxide and ammonia or nitrous 

 acid with a few mineral salts. They are thus prototrophic in the 

 strictest sense of the word, for a simpler synthesis of proteids than 

 theirs is scarcely conceivable." It cannot be said, however, in this 

 case that sulphur and phosphorus were absent, as they may have 

 been ingredients of the " few mineral salts," but in the case made 

 known by the writer so much earlier (in 1871) the Bacteria and the 

 Torulas have in some way to build up their substance from the 

 elements entering into the composition of distilled water, tartaric 

 acid and ammonia — and this surely must be the simplest known 

 mode of origin of protoplasm, as C, H, O, N seem alone to 

 have entered into its composition. Yet any one can test its reality 

 by adding a single drop of a turbid hay or beef infusion to an 

 ounce of distilled water in which ten grains of neutral ammonium 

 tartrate is dissolved. If this solution thus inoculated with common 

 micro-organisms is kept at a temperature of about 80° F (27° C.) 

 for a couple of days the clear fluid will have gradually become 

 opalescent from the growth of myriads of Bacteria, and perhaps 

 some ToruljE, and after a time it will become quite turbid as their 

 numbers increase." 



' In an experiment of this kind, recently made, in which a drop of a hay 

 infusion was used as the inoculating agent, the tartrate of ammonia solution 

 only became very slightly opalescent even after several days, but on examination 

 this opalescence was found to be due almost solely to minute sifigle and budding 

 Torute. See Note i, p. 69; and 'Knowledge,' Aug., 1905, p. 199, for some 

 additional details In regard to this whole subject. 



