424 



NA 7 URE 



[March 5, 1885 



The result of the analysis showed 8-24 per cent, of the whole 

 to be carbonic acid gas (absorbable by caustic potash). Of what 

 remained 24-8 per cent, was oxygen (absorbable by pyrogallic 

 acid and caustic potash mixed). The residue, 75'2 per cent., 

 was, I presume, mainly, if not wholly, nitrogen. I ought to 

 remark that my pump was furnished, as is usual, with the phos- 

 phoric aciil drying tube. The gas, therefore, which I collected 

 was perfectly dry, and I have no way at present of ascertaining 

 how much moisture adheres to the spun glass. In stating the 

 results of the analysis I have made no correction for moisture 

 introduced with the potash solution. 



In order to make an estimate of the amount of. surface exposed 

 by the spun glass, I measured, with a screw micrometer gauge, 

 the diameters of 200 of the fine glass fibres taken at random. I 

 found them, as I expected from the care with which they had 

 been prepared, fairly uniform, and the average diameter was 

 7-06 hundredths of a millimetre. Weighing also the 200, and 

 then the whole quantity, 1 found the whole number of the fibres 

 to be 6370. The average length was 10-25 cm. The surface 

 was thus 1448 sq. cm., or equal to that of a square 38 cm. in the 

 edge. 



I am preparing for further experiments on this subject, and 

 h ipe soon to be able to add to it observations on the amount 

 and on the electric conductivity of the film of moisture condensed 

 upon the surface of glass. 



Additional Note. — Since the writing of my former communica- 

 tion on this subject, I have made some further experiments on 

 it, and I beg leave to give an account of the results of one of 

 these experiments. 



Having filled a fresh tube with fresh spun glass, I carefully 

 exhausted with the Sprengel pump on January 24, and the 

 exhaustion was kept up till February 5 — that is, for twelve days. 

 During this time I frequently tested with the McLeod gauge. 

 A very slight increase of pressure was found during that 

 interval, but it was so slight that I am not able to say that it 

 was greater than that which is observed at all times, even with 

 the Sprengel pump in excellent order, when a vacuum is main- 

 tained for several days. 



On February 5 I passed three or four bottlesful of mercury 

 through the pump, and had a vacuum of about 0-5 M> as 

 shown by the McLeod gauge. I then applied heat, and had 

 instantly an abundance of gas given off from the spun glass. 

 This was collected as before, and analysed. 



The number of glass fibres was 15,500, giving an estimated 

 surface area of 3527 sq. centims. The amount of gas given oft 

 was 0-41 c.c, which is considerably less in proportion than in 

 my first experiment. 



Of this gas it was found that 78-6 per cent, was carbonic acid 

 gas (absorbable by caustic potash). Of the remainder 10-5 per 

 cent. was oxygen (absorbed by pyrogallic acid and potash), 

 while 89-5 per cent, was left unabsorbed, and may be supposed 

 to be mainly nitrogen. 



The very large proportion of carbonic acid gas is remarkable, 

 and it is difficult to account for, unless we may suppose that it 

 was taken up by the glass in large quantity during the operations 

 of drawing out the glass into fibres and inclosing it in the 

 containing tube — operations during which there was, in these 

 preliminary experiments, an abundant supply from the blowpipe 

 flames. 



Chemical Society, February 5. — Dr. W. H. Perkin, 

 F.R.S., President, in the chair. — A lecture was delivered "On 

 Chemical Changes in their relation to Micro-Organisms," hy 

 Professor Frankland, F.R.S., a plant being defined as an 

 organism performing synthetical functions, or one in which these 

 functions are greatly predominant ; an animal, as an organism 

 performing analytical functions, or one in which these functions 

 greatly predominate. The micro-organisms were cla sed by the 

 lecturer among animals. Their life essentially depends upon the 

 taking asunder of more or less complex compounds, resolving 

 them into simpler compounds at the expense of potential energy. 

 As micro-organisms are commonly termed " ferments," and their 

 analytical operations "fermentations," it is necessary to sharply 

 distinguish between organised ferments and certain bodies which 

 bring about analogous chemical changes, but which are not only 

 not organised, but exist in solution. These latter, or "soluble 

 ferments," as they are commonly termtd, are said to act by 

 contact : they produce certain chemical changes in the ferment- 

 escible substances without themselves furnishing from their own 

 substance any of the products of change ; the effects they produce 

 are esseniially analytical, consisting in the as^imila'ion ol water 



and the splitting up of the fermentescible substance into two or 

 more new molecules, and may be brought about by purely 

 chemical means. They differ only, or chiefly, from the organised 

 ferments in that they are unorganised and do not increase in 

 amount during their action upon fermentescible substances, of 

 which a very large, although limited, quantity may undergo 

 transformation by the action of a very minute quantity of the 

 ferment. A list of changes brought about by unorganised 

 ferments was given. In that portion of the animal kingdom 

 with which we are best acquainted, oxidation is the essential 

 condition of life : it is the kind of action by which the animal 

 changes actual into potential energy. The changes effected by 

 micro-organisms are essentially of the same character as those 

 brought about by the higher orders of animals : that is to say, 

 they are all changes by which potential becomes actual energy. 

 With one or two exceptions, the chemical changes effected by 

 micro-organisms — unlike those produced by soluble ferments — 

 cannot be brought about by other means. The observations of 

 Hatton and others have shown that micro-organisms retain their 

 vitality in presence of a variety of substances which rapidly 

 prove fatal to higher animals ; the unexpected fatal effects of 

 pongy iron would seem to promise, however, that there are 

 substances fatal to bacterial life which have no t >xic effect on 

 more highly organised animals. It has not yet been shown that 

 any degree of cold, however intense, is fatal ; animation may be 

 suspended, but it is restored when the temperature rises. With 

 regard to heat, the lowest fatal temperature recorded is 40 C, 

 but many species can withstand much higher temperatures. 

 Chloroform and compressed air are said to arrest their action, 

 but have no influence in preventing the changes brought about 

 by unorganised ferments. The position of micro-organisms in 

 nature is only just beginning to be appreciated ; their study both 

 from chemical and biological points of view is, however, of the 

 highest importance to the welfare of mankind, and leads the 

 inquirer right into those functions of life which are still shrouded 

 in obscurity. In the course of the lecture the best known micro- 

 organisms and the chemical reactions due to them were passed in 

 brief review. Prof. Frankland also referred to the following 

 results of an experiment made in the month of June, in which 

 fresh urine was allowed to stand for 25 days in a clean glass 

 vessel : — 



The results of these observations and determinations which 



