252 EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 



ducted with the profoundly scientific spirit which characterizes all his 

 labours, and might perhaps have been deemed sufficient to convince 

 naturalists as to the truth of the fact, and to serve as a basis to subse- 

 quent inquiries. 



But the results thus obtained carried little weight, and it would be 

 easy to give a long list of naturalists, who, even at present, deny in the 

 most positive manner, what has been termed the revivification o/Rotifera. 



Latterly, it is true," M. Schultz has successfully repeated some of 

 Spallanzani's experiments, and has furnished many naturalists with the 

 opportunity of making similar researches ; but still more lately, M. 

 Ehrenberg has added the weight of his great authority to the opposite 

 opinion, and having formally rejected the opinion of Spallanzani, has 

 attempted to explain the way in which an error of the kind could find 

 its way into science. 



This interesting and much debated question, then, could not be con- 

 sidered as definitively settled, and appeared to demand further investi- 

 gation. It was necessary to examine carefully all the circumstances 

 attending the phenomena described by Leuwenhoeck, Needham and 

 Spallanzani, to submit to the proof of experiment, the objections and 

 hypotheses presented by others, antagonists of these celebrated observers, 

 and to acquire new facts by which one or other of the contradictory 

 opinions of naturalists might be supported or refuted. This difficult 

 task has been undertaken by M. Doyere. 



The Rotifera and the Tardigrada are found, as is well known, in the 

 moss growing upon roofs, or in the sand found in the gutters of the 

 roof, and are seen in the living state, when these matters, after having 

 been for a long time dry, are wetted with water. The fact of the 

 appearance of these animalculae in a living state in dust which had been 

 dry during months, or even whole years, can no longer be disputed, and 

 it is equally well demonstrated that, with these minute beings as with 

 animals of a higher class, evaporation of their fluids, carried to a certain 

 extent, induces the abolition of every sign of vital motion. The parti- 

 zans of Spallanzani's opinion regard the reappearance of these living 

 beings as a sort of resurrection ; and the advocates of the contrary 

 opinion think that the phenomena may be explained in a simpler man- 

 ner ; the opinion of some is that the Rotifera, &c., are of an amphibious 

 nature, and capable of living in dry air as well as in water or sand, 

 where the moss with which they are surrounded would preserve them 

 from too complete desiccation, so that in fact, in the above cited 

 instances, the active state of the animalcule would never even be inter- 

 rupted, and these little animals buried in apparently dry dust, would 

 still meet with sufficient humidity to prolong their lives and to allow of 

 reproduction, so that those which have been supposed to become revivi- 

 fied would be in reality, to use the expression of M. Ehrenberg, only 

 the great-grandchildren of those observed in the same material at the 

 commencement of the experiment. According to other naturalists, the 

 desiccation of the sand or moss containing the Rotifera, would infallibly 

 kill the animals themselves, but would not destroy the vital principle in 

 the ova which they may have deposited, and, consequently, instead of 

 witnessing the resurrection of the animals themselves, we only see the 



