The modes of origin of lowest organisms

50

The vapour had lost all odour of turnip. Some of the fluid which splashed over was found to be still slightly acid.

51

This experiment is very interesting in two or three respects. A neck of half the usual length – with only four bendings – sufficed to preserve the fluid for several days; and when this fluid (which had been in the bent-neck apparatus for nine days) was sealed up in the same flask during ebullition, it remained in vacuo for thirteen days without undergoing any apparent change, and then only became turbid under the influence of a higher temperature. Yet some of the same fluid, in a flask which was hermetically sealed during the first ebullition (No. XV.) behaved as such an infusion usually does, and became quite turbid in forty-eight hours.

52

Flask still in my possession, unopened.

53

The filtered infusion of turnip was neutralized by liquor potassæ. The cheese (Cheddar) was new and not in the least mouldy.

54

The fluid itself being somewhat opaque, the first stages of increased turbidity from presence of Bacteria could not be detected.

55

This again is a most instructive experiment when compared with Nos. XVI. and XX., in which portions of the same infusion were employed. The results in No. IX. would lead us to believe that a vegetable infusion which does not ferment, does, nevertheless, undergo some changes in molecular composition, and this notion seems to derive confirmation from the present experiment. Some of the same solution which has been kept for a time (twelve days) from contact with atmospheric particles, subsequently, even when fully exposed to the air, undergoes no apparent change for six days, and then, instead of becoming filled with Bacteria, swarms only with Torulæ. Yet the infusion in this condition was perfectly capable of nourishing Bacteria, as I subsequently proved by inoculating it. Why then was it not inoculated by the living Bacteria, with which the air is thought by some to be teeming?

56

Some of the same fluid, exposed in a similar flask, without previous boiling, became turbid in eight hours, and lighter in colour; whilst, after twenty hours, the turbidity was extremely well-marked.

57

The condition of the fluid, and the nature of its contents, were very similar to that met with in No. XXI.

58

Still in my possession, unopened. In all probability the flocculi which formed would be found to be similar in their microscopical, as they certainly were in their naked-eye characters, to those met with in No. XXXV.

59

Experiment No. 8, recorded in ‘Nature,’ 1870, No. 36, p. 194, may be compared with this and No. XXXIII.

60

This experiment should be compared with Nos. XVIII. and XXXIII. It seems to show that if some fermentable fluids can be kept for a time under conditions in which they will not ferment, the constitution of the fluid, instead of remaining the same, undergoes a slow alteration by which it is rendered absolutely less fermentable, even when exposed to the most favouring influences.

61

After this experiment had been completed, a fresh-filtered infusion of turnip was placed in the same flask (having the neck open just beyond its second bending), and after having been boiled for a few minutes it was immersed in the same water-bath. This fluid became turbid in thirty-six hours, and was then found to contain multitudes of Bacteria; and the characteristic odour of the turnip infusion was still appreciable.

62

The results of this experiment are most interesting, especially if compared with what takes place when some of the same fluid is neutralized by ammonic carbonate (No. XXXIV.), with what occurs when a similar fluid (as in No. XXX.) is contained in a flask sealed during the continuance of ebullition, or also with what occurred in Nos. XIII. and XXXII. In the present case the second boiling seems to have destroyed what small amount of fermentability there was still remaining in the solution; but in No. IX. fermentation did take place after the second boiling – though this occurred only under the influence of diminished pressure and a higher temperature.

63

Some of same as that which was used (unaltered) in last experiment.

64

It had been rendered turbid from the first, by the carbolic acid.

65

The fluid had been rendered paler and turbid from the first, by the addition of the carbolic acid.

66

The alteration in colour was less marked than in the similar mixture which had not been boiled, though the turbidity was just as obvious.

67

This fluid was whitish, and somewhat opaque, from the first.

68

For other experiments showing a similar sterility, induced by a slight acidification with acetic acid, see ‘Nature,’ 1870, No. 37, pp. 226 and 227.

69

The results of this experiment, and of No. LXIII. are decidedly opposed to the reality of the germ-killing powers with which carbolic acid has been endowed by Professor Lister and others. I, however, had previously found that specimens of Torulæ and Bacteria, obtained from freshly opened flasks, and then mounted as microscopical specimens in a mixture of glycerine and carbolic acid (in the proportion of 15:1), not unfrequently grew and multiplied under such conditions. MM. Béchamp and Estor, also found that Bacteria multiplied in carbolized fluids, and similar facts have been testified to by some Italian observers. But, organic fluids differ much from one another, so that the influence of carbolic acid may well be different upon different fluids. And, accordingly, we find that whilst its addition to, and subsequent boiling with, a hay infusion increases the fermentability of this, precisely the opposite effects are produced when the hay is replaced by a turnip infusion (see No. XLV.). Without wishing to undervalue in the least the system of treatment introduced, and so admirably carried out by Professor Lister, I am strongly of opinion that he explains his results by theories which are almost wholly incorrect.

70

All the simple ammoniacal solutions were in the proportion of ten grains of the salt to the fluid ounce of distilled water; and to those which also contained sodic phosphate, three grains of this were added. About half an ounce of each solution was put into a one-ounce wide-mouthed bottle, and then tightly corked.

71

On comparing the corresponding experiments of series XLVIII.–LI. with those of series LIII.–LVI. less difference is found than might have been expected by many. The comparison of the numbers of each series with one another, also reveals the interesting fact, that the mere presence of N, C, O, and H, is not all that is required, even for the growth and nutrition of the lower living things. These elements seem to lapse into the new combinations constituting living matter of various kinds, more easily from certain pre-existing states of combination than from others. Solutions of ammonic tartrate are much more favourable starting points for the new combinations than solutions of ammonic acetate. The comparison of experiment No. LI. with No. LII. is extremely interesting in reference to the dogma that phosphorus is a necessary ingredient in living matter. Solutions of the ammonic tartrate in distilled water have been twice analyzed for me by a skilled chemist, without revealing the least trace either of phosphorus or sulphur. This result is very remarkable when compared with the amount of living matter which may so soon appear in such a solution: the number of the organisms and the rapidity of their evolution, being almost equal to that which occurs in a similar solution to which a phosphate has been added. However much, therefore, phosphorus may aid the development of organisms in many fluids, there is still an important difference between many and all, which if more frequently borne in mind, would render universal propositions more scarce (see ‘Journal of Chemical Society,’ March, 1871, pp. 72–74). The truth of the dictum “Ohne Phosphor gar kein Leben,” is, I venture to think, far from being proved. If on insufficient evidence (referring only to particular fluids) such a dictum is arrived at; and if then, the presence of organisms in any fluid is to be taken as evidence of the existence of phosphorus (even though this cannot be otherwise substantiated), the case of phosphorus in relation to Life comes to be similar to the case of the much abused germs.

    Mutato nomine, de te

Fabula narratur

72

The fluids were boiled at the low temperature, with the aid of an air-pump, merely in order to be able to procure a more perfect vacuum in the flasks; these experiments being destined to show whether the simple (uninoculated) solutions would become turbid in vacuo– that is to say, without the oxidizing influence of the air – when they had not been exposed to an amount of heat sufficient to destroy any living or dead ferments which they might contain.

73

A deposit of this kind is almost invariably found in such solutions after their fermentability has been lowered by previous boiling. Growth takes place very slowly in these cases, and also when similar boiled fluids are contained in vacuo.