206 CLASS VI. 



that this animal, which he had found in a leaden gutter of his house, after 

 it had been dried with the sand and other matters that adhered to it, 

 revived again, when after two days he poured water upon it, which, having 

 been previously boiled, could contain no living animalcule. He afterwards 

 found that the same phenomenon occurred after a lapse of five months 

 (bl. 413). Different observers repeated these experiments. FONTANA 

 found Wheel-animalcules that had been dried for two years and a half 

 revive on being moistened (Traite sur le venin de la Vipere I., Florence, 

 1781, 4to. pp. 90, 92), and SPALLANZANI saw the waking from slumber 

 occur even after four years (Opuscules de Physique, traduits par J. SENEBIER, 

 Geneve, 1777, II. p. 310). The last-named observer saw the same pheno- 

 menon many times in succession ; nay, even eleven times he saw alternately 

 apparent death and life. A few minutes are often sufficient to revive the 

 creatures ; but such alone as were surrounded with sand and other matter, 

 not those which lying quite bare had been dried, were revived. Observations 

 in the present century also are not wanting, by DUTROOHET, C. SCHULTZE 

 (according to EHRENBERG on Philodina), and others. 



This phenomenon does not stand quite alone. We have spoken above of 

 Anguillula (p. 194), and SPALLANZANI observed the same phenomenon in a 

 microscopic aquatic animal, which he named Tardigrade, and which has 

 been called Arctiscon by other writers. DUJARDIN brings this and other 

 similar animals as well as the Wheel-animalcules into the same class of 

 Systolides; but we are of opinion that they ought rather to be placed, as 

 very imperfect forms of Arachno'idea, with the Acari. It is on these tar- 

 digrades that DOYERE not long ago performed his very interesting experi- 

 ments, and also, after most perfect desiccation of the animals when quite 

 uncovered, succeeded in reviving them (Ann. des Sc. not. 2 e geVie, 1842. 

 Tom. xvni. Zoologie, pp. 535). 



To these observations no exception can well be taken ; the facts must 

 either be stoutly denied or be accepted as we find them. SPALLANZANI 

 asserted incorrectly that life was quite gone, and that a real revival 

 occurred (1. 1. p. 322). LEEUWENHOECK expressed himself more cautiously. 

 BONNET too speaks of a seeming death, and says that life is not quite 

 extinguished (Consid. sur les corps organises, (Euvres, Neuchatel, 1779, 

 8vo. vi. p. 224, Contemplation de la nature, ibid. Tom. vm. p. 262). VON 

 HUMBOLDT calls the state of apparent death in these animals one of sleep, 

 or of suspended life (Versuche uber die gereizte Muskel-und Nervenfaser, 

 1797. 8vo. I. s. 296). In this desiccated state life is potentially present, 

 but does not announce itself by actual phenomena. If we choose to name 

 this life latent, we must not call death itself a latent life; certainly these 

 animals are not dead, but their life is brought to a stand by the want of 

 one of the most common and most necessary of vital stimuli, by the want 

 of water. 



