28 M. Doycre on the Revivification of Animals of the 



them, and to trace in each separate individual all the phases 

 of desiccation ; to observe them gradually assume the appear- 

 ance of dead bodies, and to determine afterwards that these 

 same bodies, dry and brittle, are susceptible of reassuming 

 their primitive form, and of returning to life, under the in- 

 fluence merely of a few drops of water. 



This experiment appears to be decisive ; but it may still be 

 asked, whether the drying which the animalculre have under- 

 gone has been complete, and if the privation of all the water 

 contained in their tissue, would not render them incapable of 

 resurrection, after having in this way passed years in a state 

 of apparent death ? 



In order to determine satisfactorily this highly interesting 

 and physiological question, M. Doyerehad recourse to the most 

 powerful means by desiccation employed by chemists in the 

 analysis of organic substances. He suspended for five days, 

 in the vacuum of the air-pump, over a vessel containing pure 

 sulphuric acid, some Tardigrada surrounded with sand, or un- 

 covered and dried upon slips of glass ; and he left others dur- 

 ing thirty days, in the Torricellian vacuum, dried by chloride 

 of calcium ; and in all these instances, he obtained some re- 

 surrections. These results are of great importance towards 

 the solution of the question which M. Doyere had proposed 

 to himself; but he still conceived that they might be con- 

 sidered as offering only a strong probability in favour of the 

 complete desiccation of the animalculae, in which the faculty 

 of becoming revivified was retained ; he continued his experi- 

 ments, and by studying the influence of elevated tempei'atures 

 upon these singular beings, he arrived at the discovery of 

 most decisive and surprising facts. 



It is well known that animals perish when their tempera- 

 ture is raised above a certain limit ; inferior, however, to that 

 at which the white of egg coagulates, and which in the ma- 

 jority of cases does not exceed 50^ cent. (122'' F.) Animal- 

 culae capable of resurrection are not exempted from this law. 

 M. Doyere is satisfied that the Rotifera and Tardigrada perish 

 when the water in which they swim is heated to 45" cent. 

 (113" F.), and that they cannot then be recalled to life by any 

 means. But he has found that this is not the case when the 



