io8 POPULAR SCIENCE MONTHLY. 



cover of a wooden box in a compressed-air refrigerator for 

 meats, where they were exposed for a hundred and eighteen 

 days to repeated but not continuous refrigerations, most of 

 which lasted twenty hours each. The lowest temperature reached 

 was - 53-89 C. (- 65 F.) ; the highest, - 37'78 C. (- 36 F.) ; and 

 the mean, 41*93 C. ( 43'4 F.). After each refrigeration the 

 temperature rose to that of the interior of the receiver, but slowly, 

 while the refrigerations were rapid. 



After the conclusion of the experiment, when taken out of the 

 refrigerator and planted, the wheat, oats, and fennel came up 

 promptly; only thirteen out of sixty seeds of sensitive plants 

 germinated, and of lobelia seeds, which were too small to be 

 counted, only ten. The failures of the sensitive-plant seeds could 

 not all be attributed to the cold, for others of the same species 

 which were not refrigerated did but little better. The lobelia 

 seeds were, however, certainly killed by the cold, for the control 

 seeds germinated abundantly. It is safe, too, to infer that seeds 

 can remain inert and unharmed in a medium unsuitable for respi- 

 ration, provided nothing is present to injure their protoplasm 

 through chemical action. Such a medium, for example, would be 

 an atmosphere of carbonic acid. 



I desired to ascertain the effects on germination of keeping 

 seeds in vacuum. The most obvious way of trying this experi- 

 ment, by the formation of a barometrical vacuum, was liable to 

 the objection that the abrupt removal of the air and moisture 

 might disturb the tissues and modify the structure and compo- 

 sition of the protoplasm of the seeds, and thereby produce a 

 complication of results. I therefore tried another way, by im- 

 mersing them in mercury under such precautions that no air 

 could reach them other than what they contained within them- 

 selves. The results agreed substantially with those obtained by 

 refrigeration, and go to confirm the view that seeds can continue 

 to subsist in a condition of complete vital inertia, from which 

 they recover whenever the conditions of the surrounding medium 

 permit their energides, or the living masses of their cells, to re- 

 spire and assimilate. 



At first sight, this return to life resembles the resumption of 

 motion by a machine that has been resting when it is put into 

 communication with its motor a comparison which has been 

 often made. But the phenomena are not of the same nature in 

 the two cases, and the energides, of which the total constitutes 

 the living individual, are not machines in the usual sense of the 

 word. For a machine works without changing its structure, 

 while the energides segmentate after they have grown, and their 

 segmentations operate in their turn as energides. This is because 

 the matter assimilated by living protoplasm augments its mass 



