22 



♦ KNO\A^LEDGE ♦ 



[NOVEMBEE 1, 1888. 



nothing had happened — then our methods of inv&stigating 

 living bodies would be essentially .simplified, and we might 

 hope to establish the necessary conditions for each separate 

 function. 



This production of life at pleasure, this winding up and 

 stopping the clock of life, is in some cases subject to the will 

 of man. Nature herself performs the experiment millions 

 of times, on a large scale or on a small one, on plants and 

 animals, on seeds and eggs, as well as on completely formed 

 beings, when in summer it dries up the organic dust and 

 then after weeks of drought restores it to life by invigorating 

 rains, or when by currents of air nature transplants it to 

 damp regions and awakens it to new life. 



The unwearying Leeuwenhoek was the fii-st to make these 

 fundamental observations. In bis l-l-lth letter on the 

 revealed mysteries of nature he describes a series of 

 infusoria, especially radiate animals, which on August '25, 

 1701, he found in the water of a hou.se gutter. This water 

 he evaporated, and when, as late as February 1702, he took 

 up the drj' residue, he saw, to his great astonishment, that 

 without exception the infusoria came to life again on being 

 moistened with pure rain water. He thought that all the 

 species resuscitated by him had thick shells which in the 

 process of drying did not permit the water in the interior to 

 evaporate. But this view, which was shared by later 

 scientists, is incorrect, because the sun'ounding skin or 

 shell — which does not exist on all species — is not so thick as 

 would be required for this. The animals rather shrink 

 enormously, as may easily be seen with powerful magnifying 

 glasses, so that they become unrecognisable and evidently do 

 not contain water within the crust or shell. It is also 

 possible in fifty-seven other infusoria, especially in dried 

 ursidi, to note the swelling of the body and the extremities 

 when they are moistened. This is one of the most beautiful 

 spectacles which the microscope affords, for we see how the 

 supposed j)articles of dust which only an adept can distinguish 

 from the surrounding real dust, and then principally by their 

 colour, are brought into life. 



The second observer was Turbervill Needham. In the 

 summer of 17^13 he discovered in diseased wheat little 

 eel-like bodies which were wholly motionless and fomied a 

 thick confused mass. He moistened them, so as better to 

 observe the supposed fibres, and was highly surprised when 

 they thereupon became alive. He was greatly perplexed at 

 this accidentally discovered fact. He kept the mites for 

 two years in a dry place, and ever and again they would 

 come to life through the influence of water. His observa- 

 tions were confirmed and extended in the same year by 

 Henry Baker. This scientist saw the diied animals come 

 to life by moistening after the lapse of twenty-seven years, 

 just as after a few years. Similar re.sults in respect to the 

 same subject were attained somewhat later by Buffon, who 

 established his priority against the gi-eat physiologist Fon- 

 tana, who, independently of all others, made the same 

 discovery in 17C<7, Buffon's account, however, is somewhat 

 j)Oor; and when he coiTectly observed and compared the 

 anguillulje with little machines, he confused this good 

 thought by his broader, phantastic statements respecting the 

 living molecules. 



Fontana, with brilUant success, extended his attempts at 

 i-esuscitation to other animals. He dried, besides the 

 anguillulinie, especially radiate animals, a hair worm, and 

 then brought it to life again by means of water. He felt 

 allied upon " to speak of this little wonder in a special 

 treatise under the title, ' On the Life and Apparent Death 

 of Animals.' " This treatise, however, is not extant. 



The most extensive investigations respecting the resus- 

 citation of Lifeless animals were made by Spallanzani, who, 

 in 1776, p\iblished in Modena his great work on animal 



and plant physics. By drying them he could make the 

 same rotifers lifeless, and by moistening them restore them 

 to life eleven times. He found further that even at 19° 

 below the freezing point of water and at a compaiatively 

 stronger degree of heat the dried animals still ret;iined 

 vitality. He it was who discovered the v.rsuli, which are 

 espec'.all}' serviceable for such experiments, and which, being 

 equipped with nerves, muscles, and eyes, are far more highly 

 organised than any other animals revivified by him. 



This remarkable creature was first experimented with by 

 C. A. S. Schultze, the first German scientist who turned his 

 attention to the resuscitation of life. Discovered in Holland, 

 confirmed in England and France, extended and more 

 accurately established in Italy, the fact of revivifying small 

 organisms made the rounds of half Europe without even a 

 sinyle fundamental investigation being made in Germany 

 during more than a century. And after Schultze had 

 published his observations in 1834 the fact was doubted 

 by German scientists, and indeed utterly denied by Ehren- 

 bei'g. In 1838, therefore, Schultze, on the occasion of a 

 scientific convention in Freiburg, again .set forth his dis- 

 coveries. Here he showed those animals which had been 

 called shell-animals, by Hufeland, but which he had named 

 macrobiolus on account of their longevity. But Ehren- 

 berg's strange explanation that presumably the supposed re- 

 animated individuals were the descendants of the dried ones 

 still for a long time kept scientists from accepting the new 

 views. 



Above all, the experiments with freezing are convincing. 

 These can be performed with success on higher animals. 

 Frogs, as I myself have repeatedly shown, can be frozen in 

 all conditions to solid ice, so that the slightest trace of life 

 no longer exists, so that no sign of vitality can be elicited 

 irom them by the greatest irritation, and then again come 

 to life after having been thawed out, and appear just as 

 before the experiment. Dumeril, in 1852, performed such 

 an experiment with entire succes.s. Many fishes, we know, 

 especially the pike, can be frozen through and through or 

 be left lying in the air, and still be revived on being 

 moistened with water. 



With warm-blooded animals only a very few experiments 

 of this S3rt have been tried. Still it is known that a few 

 may be frozen even to the entire cessation of the heart's 

 action and breathing, even to the complete disappearance of 

 nervous and muscular sensibility, and then by careful heat- 

 ing become, for a time at least, alive again. And the chicken 

 in the egg, hiefore hatching, can be so greatly reduced in 

 temperature that the action of the heart ceases, without 

 suffering injury, if after a couple of days the normal heat 

 is lestored. It merely hatches so much smaller, since, it 

 cannot legain the lost time. Fresh eggs, again, which 

 have been frozen to sohd ice, have developed, after gradual 

 thawing, with complete I'egularity in the process of incuba- 

 tion. 



^thittoi* 



British Eeptiles and Batrachians. By Cathebise C. 

 HoFLEY. (London : Swan Sonnenschein & Co. 1888.) — 

 We shall be much surprised if the persual of Miss 

 Hopley's most interesting volume does not lead to the setting 

 up of reptilian vivaria by a large n um ber of people who, prior 

 to reading it, - classed toads, frogs, lizards, and newts 

 generally as "' horrid things," and who have tied from eveiy 

 snake which they were unable to kiU in the wUdest alarm. 

 This her latest addition to the capital " Young Collector " 

 series fully sustains the reputation of that excellent issue, 



