2l6 Merkel Henry 'Jacobs 



Certain of the most recent investigators have gone even far- 

 ther than Davis. O. Zacharias ('86), for example, on the basis 

 of several observations made on a species of Philodina has tried 

 to discredit the whole subject of the revivification of desiccated 

 animals. According to him, rotifers can resist drying no better 

 than other aquatic animals; when withdrawn from water they are 

 invariably killed. Like Bory St. Vincent he considers the many 

 cases of supposed revival to be due to the hatching of eggs which 

 by virtue of their thick shells are able to resist drying the same 

 as the eggs of insects or other animals. The fact that revival 

 is commonly supposed to occur in the presence of sand he regards 

 as strong confirmatory evidence since it is to be supposed that 

 concealed in the sand there might easily be many eggs which 

 would escape the notice of the observer. He concludes his paper 

 with the words * '*' * "es einzig und allein die Eier sind durch 

 welche die continuierliche Generation ensfolge aufrecht erhalten 

 wird." 



F. Faggioli ('91) as the result of a number of observations and 

 experiments on several species of rotifers comes to the same con- 

 clusion. Like Zacharias he regards the stories of the revival of 

 animals submitted to conditions of desiccation as myths based 

 on imperfect observations. Perhaps his position may best be 

 summed up in the following quotation from Fredericq ('89) which 

 he cites in his paper. "Les Rotiferes et les Tardigrades adults 

 meurent sans retour quand on les desseche. Mais les oeufs qu'ils 

 ont generalement dans le corps ne sont pas dans le meme cas. 

 Ces oeufs conservent leur vitalite malgre I'absence d'eau. Places 

 ensuite dans un milieu convenable et humide ils se developpent 

 avec rapidite et donnent naissance a une nouvelle generation de 

 jeunes animaux que 'Ion avait a tort consideres comme resultant 

 de la reviviscence du corps de leurs parents." 



It is seen from this short historical review that the entire subject 

 is in a very unsatisfactory state. On scarcely any point is there 

 any general agreement. All observers, perhaps, will admit that 

 it is possible to obtain living animals from sand that is apparently 

 dry but further than this there is no consensus of opinion. One 

 body of observers represented by Bory St. Vincent, Zacharias and 



