TRANSACTIONS OF SECTION B. '653 



he inverted, and the formation of the more complex molecules will be considered to 

 precede the synthesis of the less complex. It may be urged that this view simply 

 throws back the process of vital synthesis one stage and leaves the question of the 

 origin of the most complex molecules still unexplained. I grant thisator.ce; but 

 in doing so I am simply acknowledging that we have not yet solved the enigma of 

 life. We are in precisely the same position as is the biologist with respect to 

 abiogenesis, or the so-called ' spontaneous generation.' To avoid possible mis- 

 conception let me here state that the protoplasmic theory in no way necessitates 

 the assumption of a special ' vital force.' All that is claimed is a peculiar, and at 

 present to us mysterious, power of forming high-grade chemical combinations 

 with appropriate molecules. It is not altogether absurd to suppose that this 

 power is a special property of uitrogen in certain forms of combination. The 

 theory is but an extension of the views of Kiihne, Hoppe-Seyler, and others 

 respecting the mode of action of enzymes. Neither is the view of the degrada- 

 tional origin of synthetical products in any way new.^ I merely have thought it 

 desirable to push it to its extreme limit in order that chemists may realise that 

 there is a special chemistry of protoplasmic action, while the physiologists may 

 exercise more caution in representing vital chemical transformations by equations 

 which are in many cases purely hypothetical, or are based on laboratory experi- 

 ments which do not run parallel with the natural process. The chemical trans- 

 formations which go on in the living organism are thus referred back to a 

 peculiarity of protoplasmic matter, the explanation of which is bound up with the 

 inner mechanism of the process of assimilation. If, as the protoplasmic theory 

 implies, there must be combination of living protoplasm with appropriate com- 

 pounds before synthesis is possible, then the problem resolves itself ■into a 

 determination of the conditions which render such combination possible — i.e., the 

 conditions of assimilation. It may be that here also light will come from the 

 stereochemical hypothesis. The first step was taken when Pasteur found that 

 organised ferments had the power of discriminating between physical isomerides ; 

 a similar selective power has been shown to reside in enzymes by the researches 

 of Emil Fischer and his coadjutors. Fischer has quite recently expressed the view 

 that the synthesis of sugars in the plant is preceded by the formation of a com- 

 pound of carbon dioxide, or of formic aldehyde, with the protoplasmic material of 

 the chloroplast, and similar views have been enunciated by Stohmann. The 

 question has lurther been raised by van 't Hofi", as well as by Fischer, whether a 

 stereochemical relationship between the living and dead compounds entering into 

 combination is not an absolutely essential condition of all assimilation. The 

 settlement of this question cannot but lead us onwards one stage towards the 

 solution of the mystery that still surrounds the chemistry of the living 

 organism, 



RKCEIfX DiSCOVEEIES OF GaSEOUS ELEMENTS. 



The past year has been such an eventful one in the way of startling discoveries 

 that I must ask indulgence for trespassing a little further upon the time of the 

 Section. It was only last year at the Oxford meeting of the British Association 

 that Lord Rayleigh and Prof. Eamsay announced the discovery of a gaseous con- 

 stituent of the atmosphere which had up to that time escaped detection. The com- 

 plete justification of that announcement is now before the world in the paper 

 recently published in the 'Philosophical Transactions' of the Royal Society. The 

 history of this brilliant piece of work is too recent to require much recapitulation. 

 I need only remind you how, as the result of many years' patient determinations of 

 the density of the gases oxygen and nitrogen, Lord Rayleigh established the fact 

 that atmospheric nitrogen was heavier than nitrogen from chemical sources, and 



' See, e.ff., Vines' Lectures on the Physiology of Plants, pp. 145, 218, 227, 233. and 

 234. Practically all tlie great classes of synthetical products are regarded as the 

 results of the destructive metabolism of protoplasm. A special plea for protoplasmic 

 action has also been urged, from the biological side, by \V. T. Thiselton-Dyer, Jmrn. 

 Chem. Sue, 1893 ; Trans., pp. 680-681. 



