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u 2 . Light has a very great influence on the process of equivocal generation . Thus , the green matter of Priestley , which is remarkable for its property of exhaling oxygen , is produced only under the influence of light ; when water , particularly spring-water , is exposed to the sun in transparent vessels , whether open or close , this matter appears in the form of a greenish crust , consisting of round or elliptic granules , in which crust at first the slight motions of single molecules are discovered , and afterwards transparent threads moving irregularly . These changes have been most fully observed by Ingenhouss . According to Professor R . Wagner , the green matter of Priestley consists of the remains of green animalcules / the euglena viridis and others , which have died . In that case the moving threads would be independent beings , distinct from the green matter , and Ingenhouss would have committed the error of regarding different kinds of simple beings as different states of the same molecules .
" 8 . The entozoa and the spermatozoa , bodies with tails and spontaneous motions , which are seen by the microscope in the seminal fluid , even o invertebrate animals , seem to afford arguments for the spontaneous origin of living beings in organic matter . " 4 > . Treviranus found in his own experiments that , under circumstances otherwise similar , different organic beings , namely , infusoria or mould , are formed , in different infusions ; and he found that these differences did not depend on the water , but on the substances infused in it . " 5 . Treviranus observed that in one and the same infusion , under different accidental conditions , different animalcules were developed ; thus , om an infusion
of the leaves of the iris with fresh spring-water , in a long vessel covered with linen , and exposed to the sun , infusory animalcules were generated ; in another vessel , placed in another situation , the green matter of Priestley was formed . Thus also the products in the same infusion of rye with spring-water were different , when Treviranus placed a bar of iron in one of the vessels . This result seems to agree with that of Gleditsch , who found that in separate portions of melon covered with muslin , and placed at different heights , the various living organic substances , namely , mould , byssus , and tremellse , were produced in different proportions . To this might be added , that Gruithuisen states that he has found perfectly diff erent animalcules in infusions of pus and mucus . "
This constant variation of the result following variation of the condition , is what every sound biologist would expect to find , and is not so conclusive in favour of spontaneity as usually thought by those who cite it in support , because upon the oogenetic hypothesis it is explained as a variation in the nidus which permits the development of the ova . But now attend . Dr . ^ Burnett , of America , after showing that parasites of the human body confine themselves strictly to particular regions , as the JPediculus capitis always in the head , JP . vesiimenti always on the surface , P . inguinalis always about the groin ; also states that he has found vegetable parasites in the human ovum ! They belonged to a species of conferva ; similar to the yeast plant . They appeared by triplets or twos , and were about one 4000 th of an inch in diameter . It is impossible to explain their presence as spores , for the spores would be too large to be deposited from the circulation bypassing through the walls of the bloodvessels . { American Annual of Scientific Discovery , 1851 . )
In Cansfatfs Jahrcs Sericht for 1851 , ( vol . i ., ) we find that Wittich , who had observed entozoa in the hen ' s egg , made some experiments which proved that they might have reached their position by endosmose ; but the known porosity of the lien ' s egg prevents our applying this to the human ovum . To this may be added Dr . J . Leidy ' s discovery of ciyptogamic plants growing from the entozoa inhabiting the small intestine ; and we would especially commend Erasmus Wilson ' s work on Ringworm , as well as his paper in the Philosophical Transactions , -1844 , on the entozoa of the hair follicles ; they bring very strong evidence to bear on this subject .
When we iind entozoa within entozoa , and the entozoa only produced in certain diseased conditions of animal tissues , the idea of spontaneous generation cannot but recur . It is true that the old loophole of a nidus remains for every one to escape through ; there is no preventing the old objection , " May it not be that the spores , & < :. p" except by retorting . " May it not be that the generation docs spontaneously take place P" Wv have certain views respecting cell-development , and the passage from the inorganic to the organic , which make spontaneous generation a true explanation of many phenomena ; but as those views ai-e not yet before the world , we must content ourselves with the discussion as wo find it , — and that is eminently unsatisfactory , if we except Mulder ' s section .
In the Vestiges , great stress is laid on an argument by Dr . Allen Thomson—namely , " that the animalcules which are supposed ( altogether hypothetically ) to bo produced by ova , are afterwards found increasing their numbers , not by that mode at all , but by division of their bodies . If it be the nature of these creatures to propagate in this splitting or iissiparoiiH manner , how could they bo communicated to a vegetable infusion P" The argument it ) null , unless it can be shown that the animalcules do not como from ova , which is the point at issue . Dr . Allen Thomson will , on re-consideration , remember that , this fissiparous generation is common to a class of creatures thai ; do uneuuivocallv snrintr from ova . jib There is one consideration we , would submit to the upholders of oogonesis , derived from a survey of the facts . We know that the parasites whether vegetable or animal , are peculiar to certain localities , certain organs , certain conditions . The oinopota ecltaris in found only in beer and wine , tin ? t «•>?/' a of man is found only iM jnan ' s intestine , the hydatid of the liver is found only in the liver of various mammalia , tlwi intestinal worms appear only in the intoHtines , and die if removed from them ; they have been observed in the intestines of the embryo ( Miillor ); ' most animals have their peculiar entozoa ; the tinea is found only in wool that has been dressed , never in undressed wool , and the ca-nuras in found only in the brain , where it produces " staggers . " -r- - ^ Taking a survey of these facts with a view to their significance in this ^ / kJ ^ ^ « ¥ pJ * Xje , wo are led to one oftlireo results . ' € " : ' . ^ "¦ ' '¦ % f * Si ! llo /<> : ' 1 ail ( ' 'K < '' «> ble parasites have been created suh . scuucntiw t ~\^ S \ s -: 3 UJWWW (> t ) '" ' »» " < H |> eoiul disturbance for the purpose of imuvjisini r lii > s < * f-S ' V * '' WMk ? 7 \ - -V ^ f ^ i ^ S l " ; llliaril / ieH v v
with all our notions of man s later appearance on this planet ; while the argue / s of " final causes' * will be puzzled at the purpose of specially creating a camurus to give sheep the staggers . To accept the second would he as heterodox as to accept the third . For if you are to allow such immense importance to " conditions" to admit that a change in the nidus will create a change in the species , you tu mble headlong into the midst of the Development Hypothesis , which this hypothesis of Spontaneous Generation is brought forward to support ! For ourselves we accept both the ^ second and third propositions just laid down , and will support our opinion with an abstract of Mulder ' s arguments : n _ _ . _ _ _ _
merely peculiarities of the nidus in which each species is developed the varieties in the species being the result of varieties in the nidus ; the same egg giving birth to various creatures under different developmental conditions . 3 . Spontaneous generation . To accept the first : to say that the entozoa were made subsequent to man , subsequent to disease , subsequent to the civilization which produced beer and wine , dressed wool , and built wine cellars , would be to nlav lmvn «
It is an eternal mystery how molecules , organic and inorganic , unite to form substances- —unite in different ways to form different results . It is just as great a mystery with the inorganic as with the organic ; only o \ ir preconceived notions of Life make the difference . Let any man try to conceive the production of a crystal , and he will find it just as impossible as to conceive the production of a cell ; a precipitate is as mysterious as a primitive fibre . The truth is , the elements of the organic kingdom , oxygen , hydrogen , carbon , nitrogen , are susceptible of endless modifications of their primary forces—endless combinations—aswe see in the inorganic kingdom . Every change , however minute , gives change of result ; some of these combinations we call inorganic , others organic : words by which we
designate the varieties of the forces at work . That presupposed , we find the upholders of oogenesis and spontaneous generation only differ in terras , or can , at any rate , be made to agree . If we consider an ovum as an organic molecule , or organic body made up of the four elements combined in various groups , then the dictum of Harvey , omne vivumex ovo , is no doubt true . It is true also if we mean by ovum a determinate molecule : for the mites of cheese are peculiar to cheese ; and certain fungi are produced only from , peculiar plants . But if the term ovum be taken , as it usually is , in an erroneous and limited sense , to mean the germ of an individual organism produced by peculiar organs only—a germ in which the future animal is pre-existent—then observation will not bear us out . The individual is not contained in the egg ; and Harvey was one of the first to show this .
The supporters of spontaneous generation meet the supporters of oogenesis , and agree with them in saying that there are certain organic molecules capable , under fitting circumstances , of evolving something new , whence individual plants and animals may finally he evolved . Why may not cheese , for instance , be an aggregation of ova , or organic molecules , from which a mite may be produced as from the ovum of an insect P It cannot be denied that the existence of spermatic animalcules proves that animals or their germs gradually growing , by merely floating in a fluid ,
may be secreted . The existence of entozoa points to the conclusion that they may be produced from organic molecules , as every organic globule of mucus , milk , blood , &c , is produced . As the germs of the spei * matic animalcules are secreted animal germs , so may the molecules of casein be the ova of mites though they remain as casein . The one idea does not exclude the other . An ovum and an organic molecule aro identical : they consist of elements which arrange themselves under various circumstances in various forms , attract other elements , incorporate them , and unite into definite compounds .
To these observations of Mulder we would fain add some more abstract considerations , did space permit . Where he suggests that cheese may bo tho aggregate of certain molecules , each of which is capable , under fitting conditions , of assuming an independent life and development as a mite , he is touching upon a speculation we hope some day to lay before tho reader with adequate illustration . We may briefly indicate its direction by saying that , whereas every organ , as wolll as every animal , is composed of countless individual calls -which have lost their individuality in the association , we have only to suppose tho association destroyed , and then tho cell , regaining its individuality , is developed into a higher form , instead of remaining a portion of tho tissue . It is from the association , of a inult itudo of cells , which , otherwise , would have independent life , that more complex animals arc formed . The lowest types aro cells which spontaneously divide ; the next step is an association of cells ; the third is a transformation of those associated cells into a tissue : so that the lifo
becomoB less and less independent in the associated coIIh , and more and more collective . But as tho association may at any time and in any place be destroyed , and as the development of certain cells in the liver , the brain , or the intestine may bo accelerated beyond tho normal point of hepatic , cerebral , or intestinal development , an entozoon may be produced at the expense of the tissue , or a vegetable may be produced if tho development 1 ' bo less potent , and thus we ; have sluggers or ringworm , tapeworms or cancer .
It rimy be objected , and justly , to the foregoing , that , inasmuch as \\ a presuppose an organic tissue or blastema for tho production of these plants und entozoa , wo have not aided the cause of spontaneous generation , because the oogenetic defenders might say omnc nivurn ode vino was their position , and spontaneous generation demands that tho animal or plant ho formed from the inorganic world . We think , however , that Mulder's argument Hetties this portion of the subject . W the organic molecule ho but an arrangement oi vlcnHnnla of inorganic substances , all that is needed is , that the conditions for such an . arrangement—thosyuthesis , be present . We believe wo have ascertained what those ? conditions are ; but of that hereafter .
The world ib one incessant manifestation of . Life . Nature knows not the distinctions made by man , for his convenience . We , for our purposes , may separate tho inorganic from the organic , as wo separate tho vegetable from tho animal , and animals from ouch other , and from man ; but looking
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12 S 0 tf H fi LEADER . [ Saturday
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Citation
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Leader (1850-1860), Dec. 25, 1852, page 1236, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/l/issues/vm2-ncseproduct1966/page/16/
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