2] DESICCATION AND PROTOPLASMIC FUNCTIONS 63 



slide will not survive desiccation, on the ground that the sand 

 forms a necessary retreat in which the organism can quietly 

 encapsule itself. Of the fact of such encapsuling there can be 

 no doubt ; it is abundantly substantiated by the testimony of 

 HUDSON ('73 and '86). There is a doubt, however, whether 

 this encapsuling is a phenomenon common to all organisms 

 which can resist desiccating influences, and, therefore, whether 

 DA vis's explanation is generally applicable. To sum up : I 

 believe there is no sufficient evidence that an adult organism 

 or active protoplasm of any sort can rapidly lose all of its " free 

 water" without such a destruction of its finer structure as 

 would make it incapable of exhibiting vital activities upon 

 moistening again. 



A much greater capacity undoubtedly inheres in spores and 

 seeds. Thus KOCHS ('90) subjected perforated seeds of Zea 

 mais, Phaseolus, and Triticum vulgare to an almost perfect 

 vacuum (made by a mercury pump) for 8 days, and they nearly 

 all germinated. Even the small radish seed, with part of the 

 cuticula removed, subjected to a vacuum for three weeks ger- 

 minated perfectly. Probably there is no limit to the amount 

 of desiccation which seeds and other masses of protoplasm 

 especially adapted to resist desiccation can withstand. 



The second moot point is this : Is the protoplasm, rendered 

 immotile by drying, living or not ? SPALLANZANI prejudiced 

 the question by the title of his chapter on this matter, 

 " Observations and experiments on some marvellous animals 

 which the observer can at his will make pass from death to 

 life " ; and he and many of his successors argue that death has 

 truly occurred. PREYER ('91), however, prefers to reserve the 

 term " dead " for protoplasm which is at the same time lifeless 

 and incapable of life ; while to protoplasm which is lifeless but 

 capable of revivification he applies the term " anabiotic." The 

 question then is this, is life truly suspended during the immo- 

 tile state ? If we think of life as the sum of the chemical 

 changes occurring in the protoplasm, we shall realize that all 

 degrees of vitality, even to complete cessation of activity, may 

 occur without our being able anywhere to say at this point life 

 becomes extinct. We can hardly hope ever to deny that mini- 

 mum vital changes are occurring ; since the minimum changes 



