On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
FROM time to time we are informed that the Riddle of the Universe has been solved by the artificial production of “life” from non-living materials. But each time we wondered how it was done, for a few days, and then find out that it wasn't done at all. The riddle is still there. The expression “artificial life” has been used in recent years for two entirely different sets of ideas. On the one hand is the attempt to make artificial combinations of matter behave like living protoplasm -that is. to make live matter out of the non-living materials lying all abovt us. On the other hand is the attempt to make the eggs of various animals develop without the co-operation of the sperm-or to produce “artificial parthenogenesis,” as it has been called. Both kinds of experiments are calculated to throw much light on the fundamental nature of “life;” but they differ considerably in their methods as well as in the point of view that prompts them. We shall discuss first what has been done toward the making of “artificial life” in the cruder sense. The problem of artificial life is connected intimately with that of the origin of life, and also with that of the characteristics or distinctive properties of living matter. ]'rom earliest times there has persisted the idea that plants or animals may arise “spontaneously” from non-living matter, notwithstanding the common experience of mankind that wherever the origin of a living thing could actually be observed, it was seen to arise from another living thing. This widespread belief in “spontaneous generation” no doubt owed its tenacity to the fact that in many cases the continuity between generations could not be directly 0 bserved. For example: Eggs of eels had never been seen until within our own times; maggots were known to develop in putrifying meat, but no one had seen the flies deposit thei. eggs in the meat; the presence of tape-worms and other parasites within the bodies of human beings and otler animals; the presence of insects within the “galls” of plants, without any apparent means of entrance-all these facts served to perpetuate the idea that life can, and regularly does, arise spontaneously. The idea that all organisms arise from pre-existing organisms is a comparatively modern one; and it was accepted on philosophical grounds long before there was any actual demonstration of the principle. From the nature of the case, however, the principle omne vivum. e vivo cannot be proven, since it involves a negative. It is equivalent to the statement that living matter does not arise from non-living matter. In the seventeenth century Francisco Redi, a physician of Florence, showed that by preventing the access of insects to meat, no grubs or maggots could !be formed in it, no matter how much it putrefied. In oppositiln to these experiments, a Scotch clergyman named Needham attempted in the middle of the following century to show by means of ex p e l i ment s that “Wheat-eels” and other-animals do arise spontaneously. He showed incidentally that tiny animalcules appeared in extracts of vegetable matter, on long standing, eV!3n after these had been boiled. But his contemporary, the Italian monk Spallanzani, showed that i the decoctions • were thoroughly boiled and closed against the entrance of dust, there would be no appearance of life. Although Spal- 1 a n zan i 's experiments were not beyond criticism. his conclusions were in harmony with those accepted by practically :-ll biologists to-day-namely, that all existing plants anc animals have originated from others of essentially the same kind. But although the notion of “spontaneous generation” has been thus abandoned by all scientific thinkers in modern times, the question of the origin of life took on a new interest with the spread of evolutionary thought during the latter part of the nineteenth century. Darwin did not attempt to answer this ques- tion. He took for granted the ongm of life, in SOHe simple form, as the beginning of that evolution to higher forms which he attempted to explain with his theory of natural selection. Apart from the theory of special creation for eael species, there is only one opinion possible as to the origin of life, and that is that at some time in the past non-living material pas"ed into a living condition-in other words, that life did originate “spontaneously!” This notion of spontaneous origin 0[ life must not be confused with the older notion of the spontaneous generation of plants and animals of all degrees of complexity. Alfred Russell Wallace and others think it necessary to assume that the origin of life from non-living matter was brought about by the interposition of som' spiritual or divine influence, of the nature of which we know nothing. Charlton Bastian and another school of biologists think that the transition of nonliving matter into the living state has tal,en plaee continually from the first, and is taking place now. But most biologists accept the view that living matter originated from non-living in the very remote past, and that all living things now existing are derived by a succession of generations from the primitl\ origins. The Swedish physicist Arrhenius and the :nglishman Lord Eelvin are strong advocates of the viev! that life upon this earth was developed from primitive “germs” that were brought here in the remote past “upon the wings of light” or upon some meteorites, through lifeless space. U has been pointed out a number of times that this account of the origin cf Hfe simply shifts to some other planet or system the theater of the origin, without giving us any suggestion as to the manner of the origin. The requirements of any evolution theory are md by the assumption that life originated “spontaneously” from non-living matter at some time in the history of this planet, or of the universe. But to know whether such an assumption is warranted, we should know more about the characteristics of living matter, especially in its relation to non-living matter. Until comparatively recent times the processes going on in living plants and animals had been so little studied that the idea of life being dependent upon externl1 conditions was entertained by very few men. With the development of modern physics and chemistry, and with the application of the methods as well 'vs of the results of these sciences to the study af living things, this idea rapidly spread, until it is now pretty generally cCcepted. Moreover, the strong tendency duril1g the past two generations to unify all lmowledge, and to extend the principles of one science to the problems of all others, have stimulated the search for the physical and chemical f 0 u n d a t ion s for “vital” processes. Of all the lines of research thus developed, only three need here be discussed. The word “protoplasm” had a varied career for about twenty years; but about fifty years ago it began to be definitely applied to “the physical basis of life,” or the substance found in the cells of all plants and all animals. We know a great deal about this peculia r substance-or rather combination of substances; but there is still a great deal more that we do not know. There have been many opinions as to the structure of this living matter-that it is fibrilla, that it is like a net-work, that it is a mass (Continued on page 236.) Artificial Life of foam. The microscope does not tell us all that we should like to know-and it tells us one thing at one time, and other things at other times. It is quite possible that the “structure” of protoplasm is different in different organisms; or that it is different in different parts of the same organisms; or that it is different within the same cell under different conditions. At any rate, Prof. Biitschli, to demonstrate his idea of the “alveolar” or foam-like structure of protoplasm, mixed some finely powdered potassium carbonate with olive oil that had been heated from 125 to 140 deg, F, The oil becomes partly saponified, producing an acid. This acid reacts on some of the carbonate, producing minute bubbles of carbon dioxide. Under the microscope a drop of this frothing mixture looks like a speck of protoplasm, and the movements in it even resemble the streaming in a living cell. Some fifteen years ago these experiments were hailed by certain journalists as successful attempts to produce artifcial life. But no one who knows anything about the problem, least of all Prof. Biitschli, thought that these experiments had anything to do with the creation of life. The experiments were successful in the sense that they gave us a working model made of familiar materials, to help us understand toe minute structures and movements within the cell. How hard error does die is suggested by the fact that these experiments have been described over and over again in all grades of publications as a method for making “artificial protoplasm” until this very year. After the fact of cell-structure in organisms had hecome well establiShed, one of the prohlems that interested the experimentalists was that of the growth of the cell wall, which to all appearances is not itself alive. To test the theory that growth is produced by a stretching of the membrane with subsequent deposition of new material in the interspaces of the old wall, Moritz Traube carried on some very suggestive experiments. He allowed a solution of sugar and gelatine to come in contact with a solution of tannin through the narrow opeling of a small tube. Now as soon as- the tannin touches the gelatine it forms a m em br:ln () th 10 II g h W II i C II the wa t<)r may easily pass, but through which the sugar cannot pass at all. The globule within the membrane continues to ab sorb water from the tannin solution by osmosis, stretching the membrane. The membrane grows, and under certain cir cumstances puts forth branches in various directions, the whole taking in the appearance of some weird plants or “sea·weeds." Traube's further experiments, from 1865 on, and those of others, extended our knowledge of osmosis, threw some side lights on the mechanism of the cell-growth, and furnished amusement to many persons, for these osmotic gardens are curious and somewhat mystifying. But no biologist has in all these years suspected that Traube's phenomena were in any way related to “artificial life” until a few years ago Dr. Stephane Leduc, professor of phYSics in the medical faculty of the University of Nantes, announced that he had discovered the physico·chemical foundations of life. He presented before the French Academy of Sciences a large number of demonstrations, in which he made “plants grow from artificial seeds.” These seeds consisted of sugar plus some salt that would form a precipitation membrane with the substances of his growing medium. For example, copper sulphate in a “seed” would cause growths in a solution of potassium ferrocyanide. These growths were in no way different from those obtained by Traube and others, except that Leduc used a larger variety of substances in his experiments than had been used by other experimenters. Anyone can make for himself a garden of such “artificial plants” with very little trouble. Perhaps the easiest way is to place at the bottom of a jar a number of crystals of salts of heavy metals (e. g., sulphates of copper, iron, zinc, cobalt) and carefully pouring over them a 10 per cent solution of sodium silicate or “water glass.” The insoluble silicates of the metals will form the membranes, osmosis will cause them to stretch, variations in the density of the medium will cause irregular branching, and the colors of the salts within the membranes will give a further resemblance to “plants.” (Fig. 1 and Fig. 1a,) Leduc went farther, however, and produced imitations of living structures down to the smallest details. By placing a drop of colored salt solution into another solution of lower concentration, he produced “artifikial cells.” More definite cell membranes are produced by placing drops of 10 per cent solution of potassium ferrocyanide in. a 10 per cent gelatine solution. (Figs. 2, 3.) The appearance of nuclear division within a cell he produced by placing two drops of some solution near each other within another solution. (Fig. 4.) That all these phenomena are due to osmosis or diffusion is well known to all physicists; that they are not in any true sense identical with Hgro'vth” and “nuclear divisian” may be known only to the student of biology. Among other demonstrations made by Leduc in this connection was the formation of a “field of force” by the diffusion of liquids of different densities. (Figs. 5, 6, 7.) That the “artificial life'! of Leduc had no real bearing on the fundamental phYSiological prohlems has been shown repeatedly, and Prof. Leduc has in later statements denied that he confused his phenomena with life processes, although his original confusion is on record in the proceedings of the Academy. Perhaps the best analysis of Leduc's results is that of Prof. Maurice D'Halluin, director of the physiological laboratory at the University of Lille. This experimenter not only repeated all of Leduc's “demonstrations” but even showed that the various weird forms assumed by the “artificial plants” could be controlled by changing the concentration of the solutions, or by changing the proportions of the different materials used. Nevertheless we still find fairly frequent references . to Leduc's overstepping the threshold between the non-living and tbe living by means of “artificial seeds." In the spring of 1905 we had another “artificial life” sensation in the announcement that Mr. John Butler Burke, “of the Cavendish Laboratory of Cambridge University,” had obtained some curious,+life-Iike structures from the action of radium upon sterilized bouillon. Mr. Burke waR following up a Rugges- LEGAL NOTICES 'ATENTS If you have an invention which you 'wish to patent you can 'write fully and freely to Munn&Co. for advice in regard to the best way of obtain ing protec tion. Plea se send sketches or a model of your inve ntion and a d escriptio n of the device, explaining its operation. All communications are strictly confidential. Our vast practice, extending over a period of more than sixty years, enables us in many cases to advise in regard to patentability without any expense to the client. Our .Hand Book on Patents is sent free on request. This explains our methods, terms, etc., in regard to PATENTS, TRADE MARKS, FOREIGN PATENTS, etc. All patents secured through us are described without cost to the patentee in the SCIENTIFIC AMERICAN, MUNN&COMPANY 361 BROADWAY, NEW YORK Branch Office, 625 F Street, Washington, D. C. ATCMTC SECURED Or FEE 1 E” I S RETURNED P AT E in 1 S U lTH RNED Free rep ort 8. to Patentability. Illustratpd Guide BHoonkE. and Wbat T o InvenL witb List of Inventions Wanted aan d Pl'izes offered for inv en tion! sent free. VICTOI J. NV ANS&CO.. Wasbington. D.C. Classified Advertisements Advertisiul in this column it 7) cents a line. No les! iLhan f our nor more I Han 12 lines accepted. Count Heven words to the lin e. All o l ders must be aCOIpanied by a leillitlar.ce. Furt he r information sent on request. PATENTS FOR SALE. ARTIFIC IJAeL RAIN .-New syste m of irrigatio n comI--bined wUith electrifieId water . ,Be8t and c heaoest fertilizer. Patented. Capital w a0n18t ed t o e xp lo.it sa m. e or will weorrk on royalty basi is, E . Olsson .32 W. 9th St .,N. Y. City. F·OR SALE.-A Patent for a nfW amusemeDt devicp. The latest and most up.to·date tbriller. Write tnr fu1l information and part i culars . V. C. de Yb arrondo . 1148 West 26 t h Street, Los Ane-ele s. Calif ornia. REAL ESTATE. CALIFORNIA LAND. planted and operatec by experts. is a splendid investment. Black foS be!t of all crops. Write. Geraldson Fruit Co., Newcastle, California. (Packers Geraldsoq's Figs.) ON TH E HIGH EST H ILLS and LA R GEST L AK)S, buy your Orange Grove, Truck Land, o r Winter Home; or a .le' railroad, at a :ew town . te. For fU l l p artic ; ulars, address c. W. Brown, Frostproof. Fy! . WANTED. LOCAL REPRESE NTA tn VE W ANTED.-SDlendid income assured ri2ht man to act as OUf rePffsentative afler learning our business l.bOrOu2hly by mail. Former experience unnecessary. AlJ we require is ltone8ty, abli-ity. ambition and wiHingness to learn a lucrative busi-oess. No soliCiting or traveling. Tbis isan exceptional opportunity for a ma b in your section to Qet into a bi2 paytng bUliness without capital and become independ· ent for lite. Write at once fnr full parttculars. Ad . dre88 E. R. Marden. Pre8 .. The National Co-Operative Real Estate Company, L 378 Marden Buildinl. Wasbington, D. C. W A NTED-A man or woman to ac t 8M our information ff$ porter . AA mll or sp are time. N o exp e rien ce n necces-sa r y. at to $300 per month. Notbing to sell. Send siomp for particulars. Sales Assoc i a t ion. m AssOCia t ion Bldg. Indianapolis, In Olana. MISCELLANEOUS. "CAN 'l'HE SCIENTISTS BE MISTAKEN 1 “-Astounding iheor iesai< b8sis 1,'r K3 !;in's theor ! ,-vorrex motion. Matter does not “hold” to:eth:r, 'a -tract,” “ repel,” act at Rny distance, or act without con : tact. No *'potential” enerJ ; On. Y r'e uItimate : lement, aetb:. 'omentum (motion)I of aether g!sis of all energy, (and phenomenal; mv.true energy mP easure. “l n mazinfn! Calcuiation:” per;etual mgtion (theoret?: cal) X ased upon system of levels. Orbital vortex motion of a!>her carries ea;th: Gravity, a “push” down. Pamptf e '; ten cents, (coin). C R. Gates, Tuscola, 111. FR1E:I'-"INVE STTNG: FOR PROFIT” Magazine. Send me your name and I will mail J'u this maga:in: absolutely free. gefore y ou lnvest a dollar Cnywhere—get tillg magazine —it is wOrt\ J I r a copy r d e y cuan who int:nd” to ing est n5 or more per month. Tells a how $1,\ can grow to $22,000 —how to judge different classes of investmen.s; the Rea ' Warning :1'er o, Cf ur ,oney. This magazt ' sii months free if you wrim o_
