STUDIES IX ANIMAL LIFE. 73 



If we compare these results with those obtained 

 by M. Davaine, we can scarcely avoid the conclusion 

 that it is only when the desiccation of the Eotifers 

 is prevented by the presence of a small quantity of 

 moss or of dirt between the particles of which they 

 find shelter that they revive on the application of 

 water. And even in the severe experiments of M. 

 Doyere and M. Gavarret, some of the animals must 

 have been thus protected ; and I call particular at- 

 tention to the fact that, although some animals re- 

 vived, others always perished. But if the organiza- 

 tion of the Rotifer or Tardigrade is such that it can 

 withstand desiccation if it only needs the fresh ap- 

 plication of moisture to restore its activity all, or 

 almost all the animals experimented on ought to 

 revive ; and the fact that only some revive leads us 

 to suspect that these have not been desiccated a 

 suspicion which is warranted by direct experiments. 

 I believe, then, that the discrepancy amounts to 

 this : investigators who have desiccated the moss 

 containing animals find some of the animals revive 

 on the application of moisture, but those who desic- 

 cate the animals themselves will find no instances 

 of revival.] 



The time spent on these Rotifers will not have 

 been misspent if it has taught us the necessity of 

 caution in all experimental inquiries. Although 

 experiment is valuable nay, indispensable as a 

 means of interrogating Nature, it is constantly lia- 

 ble to mislead us into the idea that we have rightly 

 D 



