August, 1905.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



199 



The Simplest Kind of 

 ProtoplsLsm. 



A Note on the Free Growth of Bacteria and Torula;ina solution 

 of Neutral Ammonium Tartrate in Distilled Water. 



By H. Charlton Bastian, M.A., M.D., F.R.S. 



In his work on " The Structure and Functions of Bac- 

 teria," Prof. A. Fischer places the nitrifying Bacteria 

 that were discovered and isolated in 1888-91 by Wino- 

 g'radsky among his group of " Prototrophic Bacteria.'' 

 He says their life-processes are "characterised by an 

 extremely primitive metabolism — a physiological humi- 

 lity which shows them to occupy the very lowest rung 

 of the ladder of life." While on another page* he says 

 the materials from which they build up their cells are 

 " 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." He 

 further says : — "As might be expected in the case of 

 organisms with oxidising functions, all the nitrifying 

 Bacteria are aerobic. They require no light, and yet, 

 in spite of this, are able to assimilate the CO2 of the 

 atmosphere. ' ' 



His other two groups of Bacteria are supposed to be 

 absolutely separated from this primitive group : the 

 "Metatrophic Bacteria," under which are included most 

 of the known forms, because they "cannot live unless 

 they have organic substances at their disposal, both 

 nitrogenous and carbonaceous "; and the " Paratrophic 

 Bacteria," because thev "can exist only within the 

 living tissues of other organisms," that is, as true 

 parasites. 



It is the object of this article, however, to show (i) 

 that a sharp distinction between these first two groups 

 does not exist, seeing that common " Metatrophic Bac- 

 teria," as well as some Torulae are capable of taking 

 on life-processes even simpler than those shown by any 

 of the hitherto described forms of tlie "Prototrophic 

 Bacteria" ; and (2) of showing further that such simplest 

 of all life-processes are not of srobic type. 



The verification of these statements can be easily 

 made. It w^ill only be necessary to prepare solutions 

 of neutral ammonium tartrate in distilled water, using 

 about 0.65 of a gramme of the salt to 30 cubic centi- 

 metres of the water (that is ten grains to^ the ounce), 

 and often the crvstals have been dissolved to add to one 

 of the solutions a single drop of a recently prepared 

 turbid hay infusion, and to another a single drop of a 

 recently prepared turbid infusion made from beef 

 or mutton. The two solutions thus inoculated with 

 common active Bacteria may then be placed in the dark 

 within an incubator, maintained at a temperature of 

 300 — 320 C. (860 — 890 F.). In about 36 hours both 

 fluids will be found to have become slightly opalescent, 

 owing to the growth, as the microscope will show, of 

 myriads of minute Bacteria, and occasionally of a num- 

 ber of very minute Torulje. 



Though these common Bacteria and Torulse are thus 



capable of growing freely in the saline solution without 



the aid of light, I have found that light distinctly 



favours the process, since s olutions similarly inoculated 



• Loc. Cit. Truiishi , 1900, pp. 48 and 106. 



and left exposed to ordinary daylight have become 

 turbid rather more quickly, even though the tempera- 

 ture to which the solutions has been exposed has been 

 about 1 1° C. (20° F.) lower than that of the incubator. 



In order to get rid of the complication caused bj 

 the presence e\en of a single drop of an organic infu- 

 sion, such as was present at first, other solutions may 

 be inoculated with Bacteria taken from one of the 

 originfd solutions after five or six days, when their 

 turbidity has become more marked. As the Bacteria in 

 these solutions are probably less numerous and less 

 vigorous than those in the organic infusions, three drops 

 yrather than one) are now introduced into each of two 

 other freshly-prepared ammonium tartrate solutions, 

 one of which may be placed in the incubator as before, 

 and the other left in a corked flask exposed to daylight; 

 and at the lower temperature. The growth of these 

 less vigorous Bacteria is now decidedly less rapid, and 

 seems only capable of occurring at all freely when 

 aided by daylight. In the flask on the table the fluid 

 will become slightly opalescent in four or five days, and 

 this opalescence increases for a few days, when a sedi- 

 ment begins to form. But the fluid in the incubator 

 may show no distinct opalescence, even for a couple of 

 weeks or more, though a very minute amount of sedi- 

 ment will accumulate. 



Examination of the sediment taken from one of these 

 second inoculation flasks which has been exposed to 

 daylight will show masses of Bacteria, mixed with 

 Torula; or other Fungus spores, together with a deli- 

 cate, much-twisted mycelium, as shown in Fig. i. 



So far there is nothing to show that the Bacteria and 

 Torulai which grow freely in the simple ammoniacal 

 solution are not — as "Prototrophic Bacteria" generally 

 are said to be— a?robic organisms taking their CO 2 

 from the atmosphere. That point, however, was 

 settled by me as long ago as 1871, when I showed'' 

 that a solution of the same kind in a flask with a 

 narrow neck might, with the aid of an air pump, be 

 boiled at a temperature of about 900F. (so as not to 

 injure the organisms already contained in the fluid), and 

 when the air had thus been expelled, the neck of the 

 flask might be sealed during ebullition, by aid of the 

 blow-pipe flame. Experiments conducted in this way 

 showed that in the course of a few days the fluid's 

 became opalescent in the usual way within these sealed, 

 airless flasks, and the microscope revealed the usual 

 swarms of Bacteria. There was no mention in diese ex- 

 periments of Torulae having been found — though I 

 have little doubt that some of them were also present, 

 as these organisms are well known to be generally 

 anaTobic in their mode of growth. 



My claim that the organisms growing in this solu- 

 tion of ainmonium tartrate in distilled water are build- 

 ing up protoplasm in the simplest known manner may 

 be objected to on the ground of the ultimate orgajii'c 

 origin of the tartaric acid, but I am told by Sir \\'illiam 

 Ramsay that " ammonium tartrate can be synthesised 

 from inorganic material, and this substance' is, so far 

 as we know, absolutely identical with ammonium tar- 

 trate derived from tartaric acid extracted from wine- 

 lees." 



Seeing that the formula of neutral ammonium tar- 

 trate is (NH4)2 C4 H4 O4, if there were no impurity 

 in the solution, the inicro-organisms would have to 

 build up their protoplasm in some way with the aid only 

 of C, H, O, and N — which seems almostr incredible. I 

 may say that the ammonium tartrate used was specially 



'The Modes of Origin of Loicest Organisms, p. go. 



