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



"Note on the Influence of very Low Temperatures on the 

 Grerminative Power of Seeds." By Horace T. Brown, 

 F.R.S., and F. Escombe, B.Sc., F.L.S. Received September 

 27,— Read November 18, 1897. 



A considerable difference of opinion still exists amongst biologists 

 as to the condition of the protoplasts of resting seeds, spores, &c, in 

 which all ordinary signs of life may be unrecognisable for a consider- 

 able period. 



According to one view, the essential elements of the cell, during 

 the period of inertness, are still undergoing feeble but imperceptible 

 alteration, accompanied by gaseous exchange with the surrounding 

 atmosphere ; and, even when ordinary respiration is in abeyance, it is 

 assumed there are small internal changes going on, due to the inter- 

 action of certain constituents of the protoplasm, reactions which may 

 be independent of the outside gaseous medium, and which are often 

 referred to under the somewhat vague term of " intramolecular 

 respiration." 



On the other hand, it is sometimes maintained that all metabolism 

 is completely arrested in protoplasm when in the dormant state, and 

 that it then loses, for the time being, all power of internal adjust- 

 ment to external conditions. 



According to one view, therefore, the machinery of the dormant 

 protoplasts is merely " slowed down " to an indefinite extent, whilst 

 according to the other it is completely brought to rest for a time, 

 to be once more set going when external conditions are favourable. 



It appears to us that the advocates of the " slowing-down " hypo- 

 thesis have scarcely given sufficient attention to the experimental 

 evidence available, and that they have been somewhat biassed by a 

 supposed analogy between the dormant state of seeds and the hiber- 

 nating state in animals, and have also, perhaps, been unconsciously 

 influenced by Mr. Herbert Spencer's well-known definition of life, 

 which implies a constant internal adjustment in the living protoplasm. 



The experiments of the late Gr. J. Romanes, which were described 

 in a short paper laid before the Society in 1893* are full of interest 

 in their bearing on this question. Seeds of various plants were sub- 

 mitted in glass tubes to high vacua of 1/1000000 of an atmosphere for 

 a period of fifteen months. In some cases, after the seeds had been 

 in vacuo for three months, they were transferred to other tubes 

 charged respectively with oxygen, hydrogen, nitrogen, carbon 

 monoxide, carbon dioxide, hydrogen sulphide, aqueous vapour, and 

 the vapour of ether and chloroform. The results proved that neither 

 a high vacuum, nor subsequent exposure for twelve months to any of 

 * ' Roy. Soc. Proc.,' vol. 57, p. 335. 



