164 



Messrs. H. T. Brown and F. Escombe. 



lies in the fact that such processes of autoxidation, and in fact any 

 conceivable internal chemical change in the protoplasts, are rendered 

 impossible at temperatures of —180° C. to —190° C, and that we 

 must consequently regard the protoplasm in resting seeds as existing 

 in an absolutely inert state, devoid of any trace of metabolic activity, 

 and yet conserving the potentiality of life. Such a state has been 

 admirably compared by 0. de Candolle with that of an explosive 

 mixture, whose components can only react under determinate con- 

 ditions of temperature ; as long as these conditions remain unfulfilled 

 the substances can remain in contact with each other for an indefinite 

 period without combining. 



It appears to us that the occurrence of a state of complete chemical 

 inertness in protoplasm, without a necessary destruction of its 

 potential activity, must necessitate some modification in the current 

 ideas of the nature of life, for this inert state can scarcely be included 

 in Mr. Herbert Spencer's well-known definition, which implies a 

 continuous adjustment of internal to external relations.* The defi- 

 nition doubtless holds good for the ordinary kinetic state of proto- 

 plasm, but it is not sufficiently comprehensive to include protoplasm 

 in the static condition in which it undoubtedly exists in resting seeds 

 and spores. The definition becomes in fact one of " vital activity " 

 rather than of life. 



As it is inconceivable that the maintenance of " potential vitality " 

 in seeds during the exposure of more than 100 hours to a temperature 

 of —180° to —190° C. can be in any way conditioned by, or correlated 

 with, even the feeblest continuance of metabolic activity, it becomes 

 difficult to see why there should be any time limit to the perfect 

 stability of protoplasm when once it has attained the resting state, 

 provided the low temperature is maintained ; in other words an 

 immortality of the individual protoplasts is conceivable, of quite a 

 different kind from that potentiality for unending life which is 

 manifested by the fission of unicellular organisms, and with which 

 Weismann has rendered us familiar. 



In what manner and to what extent "resting" protoplasm differs 

 from ordinary protoplasm we do not at present know, but there are 

 indications, notably those afforded by the resting state of desiccated 



* The following passage from the ' First Principles ' (Section 25) clearly shows 

 that the author in constructing his definition had not anticipated the possibility of 

 a living organism attaining a state of absolutely stable equilibrium. " All vital 

 actions, considered not separately but in their ensemble, have for their final purpose 

 the balancing of certain outer processes by certain inner processes. There are 

 unceasing external forces tending to bring the matter of which organic bodies 

 consist into that state of stable equilibrium displayed by inorganic bodies ; there 

 are internal forces by which this tendency is constantly antagonised, and the per- 

 petual changes which constitute life may be regarded as incidental to the mainten- 

 ance of the antagonism." 



