LITERARY COLUMN.

Press, Volume LX, Issue 11493, 28 January 1903, Page 8

LITERARY COLUMN.

THE ORIGIN OF LIFE.

Bt Professor Benham, D- Sc, Otaco University.

(Concluded from Monday's "Press.")

3. Presuming, then, that the firs?t organism appeared on the surface of this earth by a natural process of evolution, it must have originated from non-living material, and the third theory depends on what has been termed "spontaneous generation' , or abiogenesis. The theory of spontaneous generation has held its ground for many centuries, for as :ar buck as the time of the classical philosophers we find discussions involving the idea. Aiwotle (about B.C. 350) was eoiit(?:>: to ucio;;t it. at least :us an exTibnution o! the oiigin of the lower formsui I:;-.-, aid UeitveJ. ih.K. it c<.>n«tantly oci;'. -. Fivm tiie fact that a swarm ot ft es <-an be seen to issue from a rotting i,.T.:',e, it was maintained that the flies hai oiiginatf-d f:om the dead msitter of the

<j.i;v.i'->.\ Even in mtdieval times. Bacon lit VernLaM believed that many plants — <tuh a- thistles for instance —ciiginat-ed dirtctiv h'-:u tl-K- dead earth. it was not till the 17th century Uiat the errui-i i-i' tiie theory were disposed of hv a few o::!'3!:i;ier.t.s carried out by Fiuiui.-iO ilf'.li. who dt-moiistrated th:it if ihe <;! ti.e dv.vA ;;!iini;\l be piopyrly prntertod fum ■.>.i\\i\- i \:<£ iius, tln=si no iii-.s dtveiop ti.eieni; in ulmj w:-r..:s. th* sv.'a;:ii of llies is. <>; I'iiiw: due to the fact lh..f iv tly has previously laid, its in the LCiiv;'i*e. But s-til! the idea persisted that, even if -ik'h iji.'hiy organised things as insects ■."lid i.-'it ;iii>e by spontaneous generation, vi-: in ■ .11 ■Si.-upic orjjaiiisiiis, suoii ats uiir: ~!,;(. iiu aii-e in this 11;a:11:er. i''i>: i:is!.:ui.. ; in IVoO. a. j'iiesl/ — N'.-;-!- ,- ---h.iiii by liwiine —Uiuci.'hi i,ut he li.id l'lvVf.: til-.-- i;.cL, for hu L»-ii":cd :i ile(.u:tiull of 01HiU.k , matter, and icikfd it as i-aifhtJiy ;u !,o (ou!d, .uid yet fiimul that n":i'.ie their ;:ppeaiam c in tiie iiuid. lv wa.-, hov.t-\er, pyui;cd out by lat&r ■jb-e'-veis—t-uch as Spallanzan;, .Schwann, and others—that tins was due to tenari

imperfections in the method of experimentation; for if tli. isoiutiun t>- boiled sufficiently long, and if the tube be propeiiy closed, so tina the entrance of the spores of miero-organisuts be excluded, then no iniusoiiu make their appearance in the fluid. But it was by Tyndall and by Pasteur, ia the middle of the 19th century, tihat this method was brought to perfection. Tyndall insisted on the necessity for boiling ,the fluid more than once, so as to destioy any spores of bacteria, as well as the bac-tt-ria themselves; while it htui been shown that, by means of properly baked cottonin place of a cork (so that air may have Ir.-e access, but is thoroughly filtered) —ill* entrance of spores was completely prevented on cooling. This, indead, is the maiiud em-pioy-ed daily at the present day by hundreds of lor the purpose of sterilising the fluids which they have to examine aad experiment upon. Pasteur had shown conclusively that all decomposition of organic matter id due to bacteria, and that by their exclusion pioteid matter may persist, undecomposed, for years.

By these experiments it has been established that ""spontaneous generation"—that Ls, the oiigin of living things from nonliving matter, docs not •occur at the present time. And so far as we have learnt, orguJii.Mns only originate from organisms—living tilings from living tilings. The theory of

"Abiogi-nesy-s" is discicditod, and "'Biogenesis" alone accounts for tixj appearance of new life in earth at the prcawat time.

Nevertheless, it as conceivable that spontaneous generation might, and would, occur if the condition*! were favourable. These conditions do not exist at present, but it is suggested that the earliest state of tlie earth, when still but little removed from a glowing mass, was such as to render possible the origin of life from non-living substances.

Hueckel, moreover, has drawn attention to the fact, that it is necessary to distinguish two different conditions uniter which abiogenesie may occur. These are, to quote his words, either "(a) by Autogony, in which an extremely simple organic individual originates in an Inorganic formative fluid, i.e., in a fluid which contains the fundamental substances for the composition of the organism in the form of simple and loosely conubined salts in a state of solution (e.g. carbonic acid, ammonia, and binary salts), or (b) by Puismogray, in which an organism arises in an Organic formative fluid, in which the requisite fundamental substances are in the form of complicated and fluid combinations of carbon (e.g. albumen, fats, and carbohydrates)."

Haeckel* points out that those experiments refentd to above have been limited to the latter condition, and is of opinion that it is moie probable that we should look for the origin of life under the first condition. The ea.rth, at the period at which this spontaneous generation may be supposed to have taken place, was, of course, in'a state totally different from that obtaining at tho present time. By the nebular hypothesis we are taught that the world was a glowing mass of molten material, which, in cooling, gradually formed v. cruat; tlw vap:mr surrounding the earth condensed to form rain, which, falling on this crust, helped in the process of cooling. Later on, by shrinkage of the crust, irregularities occurred, and tho water accumulated in the depressions. In this way dry land and ocean were gradually differentiated. Haeckel presume, then, that a simple mass of proteid matter originated as a result of the chemical combination of the

necessary inorganic elements present in these primary oceanic waters, combination being possible owing to the great heat and to other conditions of which we can form no adequate conception. Modern chemistry , has tended to remove much that formerly appeared to be impossible, or at least mysterious, about spontaneous generation. Till the tune wiieu Woh.er. in 1828, proclaimed and demonstrated to an astonished world his success in manufacturing an organic substance (urea) from a purely inorganic substance (cyanare of ammonia), it had been maintained that these complicated compounds of carbon, known generally as "'organic eh£imL:al substance." could only be produced as a result of the activity of living things, owing to a "vital force" or "vital .spirit" inheivnt in living things, which at that period sufficed to explain all the phenonK-na of life. But since Wohler's claissical research, constant attempts have been made, and with tonic sucoess, to manufacture in the laboratory various organic substances, and at the recent, meeting of the German Association of Naturalists and Physicians in September of last year, Professor Enul Fischer was, able to utate that he had at last succeeded in obtaining albuminoid substances by synthesis, tho possibility of which had hitherto only been dreamed of. it has then, b_-en absolutely proved that l>mt?id mattt-r can be formed from inorganic substances, under very exceptional circumstances, which are not met with in r.atnro at the present day. and there is no inheivr.t impassibility in its occurrence in the early history cf the earth's surface.

But in the last quarter of th* nineteenth ctptury » physiological chemist of high re-

pute, Pfluger by came, pointed out that, living proteids" present certain striking analogies with that very unstable fluid cvunic acid (HCNO), and showed the. very great importance of the radicle cyanogen (CN) in the. metabolic processes, especiiuly in oxidation, of protoplasm. The niaiter is altogether of too technical a character to enlarge upon here, but he points out-that carbonic acid (CO2) and ammonia (NH3) are the "ends of life, and not the beginning. That ts, he differs from Haocked., in suggesting that we must no! think of the ong:n ot organic substance as depending on the union of these (as in Haeckel's theory of amogeny), but rather look to the carbon compound cyanogen (C'N) as the more probable starting point. _ . And the great question as to tne origin of LiU\ as the origin ci l'rai.tid mattir (C-NOHS),, becomts narrowed di>wn to the oiigin oi Cvanog<.-n. Sow, organic chemistry presents us ffiai the skniiicawt fact th'ai\yajuogen and ii« ci>mix>und*, such as puossic cyanide, aoiimoiuc cyauid..\ cyanic utid, etc., oiiiy ar;e?. iv tits presence ot ki-candesc-i-nx, ileal. "Notiring is ckaitti-," says Pduger, "vluui the possibility vl the iormation ox cyauogtu compounds when th« earth was wliculy or piiiituit.y in a fiery state." Moreover, chemistry shows how some other essential constituents of pioteid, such

as the hydrocarbon and the alcohol radicle, can be foYimd synthetically in the laboratory by the aid of heat.

""It is ses-n how strongly and remarkably all facts of chemistry point to lire as the force that has produced by synthesis the constituents of proteids. in other words, .ife (say.s I'flugtr) is derived from fire, and its funduineiiucl conditions were laid down when thu eait>h was still an incandescent ii;,.:l. liie tir.se proUkl to in was living n..ii;er. uiduwvd jii all Us radicles with the of vigorously at'-i acting similar i*,.,-.i.u;".i;t*, adding thtTn chemically u> its 11U...U1.C, a,i]-i thus, giowitig ad inlinituni. Ao.-i.,iJiiig- to this hypuUi/tsss, .iving prot«d uiK-.5 not netd to have a constant muiecular uvi^iu; it is a huge moieculf undergoing i.. i:-.'.ut, iftvtr-tiidujg ;uiiii;ttiuii, and cuii--i.-1.- dtcompusiiLiun, aiul bdiavts .;v,\;:'i!;; tii.. , uiu&i chemical mtAtcules us tho

.•-..u b.-li;iVcs tuwiiidis tuiui'-'U' m-.-'itors. In tii.- given piaut iivuig uiol-.d Siiiiply coiil.Kii--- Ij do what it hjiS always du-iiu *jicf

its uii<.'iu, i.v., ii icgtittiui-ei and glows. Wo aiv, t-lioiefoi-c, by rriuger'.! theory, ltd back beyond the time supposed by Ha.jcLd tv be "tire ptliod at life comment td. J'ilUaVf'rf thvory is piatiically an expansion ol liiueik.l's, though aJoiig a slyhtlv different .iirt, itnuL-icd passible uaid ltndfi'tU probable, owing to the advances uia-d-o in Hie L'k-jiiiisuy cf pivieid. Ike begiiaungi oi living matter readi back to via time ut which th't earth's surfate Wiui still iiiLundesueiit. The compounds of cyanogeu Uuuu piastre conuliuiu.- the vnataUii mau.-iial uoui which living substance t-uok its origin. With the property of Kudv decomposition, they were fo.ced into ct/ne!atioiis with various kinds of carbon compounds, who.:.* ongji was due likewise to grutL hiat. Wiitn walur was pretipi-ia-tt-d o-u to the tai'tli's suiiitee tht-se coiupciaids envtivd into ciieuiicai relation with wait-er, and its dissolved salte and gasets, and vhus originated living pioteids—the lirst

oiyunwmsihis iirst oigani.sm must 'have been very much simpler in structure tjiun Amwba ; it was not a cell, as it had no nucleus ; and probably it was without the structural elaboration which is found in cell protop.asin today. Possibly, too, this organism nad no definite form or size.

But when once iiht.se archaic organisms were launched on this long history, we can readily imagine how advance in structure wouiu occur ; from analogy with the various degress in organisation met with today amongst the lowest forms of life they would experience the same competition as organisms do to-day; aad •evolution will account for further progress. Wβ are, by Pflugier's theory, able to account for tlud origin of prutieAd or ' living substance, and the origin of the inorganic constituents - of the earth's crust —i.e., the minerals, etc., which constitute "dust," by one and the same process, namely, the chemical and other changes wrought during the slow and gradual cooling of the ineandesoont earth. This in its turn is paiH. of the solar system, hence organic evolution comes into contact with cosmic evolution; indeed, it is a continuation of that evolution in one direction, just as geologic evolution is its continuation, side by side, in another direction. The ono line yielding us the living creatures that people the earth, the other line resulting in physical and climatic conditions to which these creatures have gradually became adapted. On* grand principle, or theory—"Evolution" —is thus siiiiicuent to account for the world as we find it; and as the value of a scientific theory is proportional to the number and importance "of the matters explained by it, as well as by the simplicity and universality of the causes employed in it as grounds of explanation," this theory has becoms so wideiy, ono may say so universally, adopted.

But even when we have dffered a reasonable explanation of life, and' of the origin of life, we have not diminished the mystery of life ; there is still much of which we are entirely ignorant. We do not attempt to explain why life" and proteids are thus intimately associated.

Wβ don't know '* how" protoplasm carries on its vital activities, or " how " nerve impulses are .transmitted, or " how" memorisation is affected. Even such a simple process—comparatively simple, com-, pared with mental phenomena—as metabolism, is enshrouded in darkness, in spite of the experimental researches of numerous* physiologists and chemists. Wβ know it to consist of a series of chemical processes, but what these are we are unable as yet to formulate with anything like precision. But this myetery," this ignorance as to much that is of importance in science, is not limited to tlie ptaenofcnena of life. Can we say " why " the two gaseous elements, hydrogen and oxygen, when brought together under certain condition?, and in certain proportions, unite to form the fluid water? Can it be said that we can explain in detail all that goes on in electrolysis? Wβ know, of course, .that certain substances pass to the anode, and others to the katliode, but can -we say " why" they behave in this way"? The current researches on physics and chemistry are yielding phenomena every bit as mysterious and incomprehensible as the study ef protoplasm. What, for instance, can exceed in mystery the phenomena of "radio-activity," of uranium, etc., so lucidly «itseribed by Dr. Coleridge Farr in this column a few weeks back? But in each case, when the facts are sufficient, thj scientific man may attempt to explain the relations between causes and effects by certain hypotheses; in many cases these hypotheses are, by their nature, incapable of demonstration. .The theory that the origin of living substance is to he traced to the union of the radicle cyanogen (ON) with afw other elements (OHa) to form protsids>, which have "lifts" as their peculiar property, appears do more (and no kss) wonderful (considered, of course, from a scientific puint of view), than that two gases, oxygen and hydrogen, each with its own peculiar properties, should, under certam known conditions, unite to form a flail with properties distinct from either of the combining gases.

Aα Lloyd Morgan says in the opening; chapter of his recent work (" Animal Behaviour'"); —"The function of biology is to formulate and to express in generalised terms the relative antecedences and sequences which are observed to occur in animals and plants. The underlying cause of observed phenomena does not fall within the purview of natural science; it involves metaphysical conceptions. It is no more (and TU3 less) a mystery than all causation, in its last resort, is a mystery."

"Gravitation, chemical affinity, crystalline force—these are all mysteries.

'•The final causes of vital phenomena (as of other phenomena) lie deeper than the probe of science can reach.' .