156 



LIFE. 



have been excited to germination when at last 

 exposed to the requisite conditions.* 



Most physiologists, at least, are content to 

 adopt this explanation, seeing that it is con- 

 formable to what is otherwise known of the 

 persistence of vitality in seeds ; but it has been 

 recently maintained that in such instances a 

 spontaneous production takes places, similar to 

 that which many philosophers have supposed 

 to occur among the lower tribes of organised 

 beings.f This is not the place to discuss such 

 a theory, of which it would not perhaps be 

 very difficult to show the absurdity; but the 

 following case furnishes, we apprehend, a very 

 satisfactory proof that seeds may preserve their 

 vitality for an unlimited time, when the ex- 

 ternal conditions are such as to prevent either 

 the active exercise of their properties or the 

 disorganisation of their structure. " 1 have now 

 before me," says Professor Lindley,^ " three 

 plants of raspberries whichhave been raised in the 

 gardens of the Horticultural Society, from seeds 

 taken from the stomach of a man, whose skele- 

 ton was found thirty feet below the surface of 

 the earth, at the bottom of a barrow which was 

 opened near Dorchester. lie had been buried 

 with some coins of the Emperor Hadrian, and 

 it is probable, therefore, that the seeds were six- 

 teen or seventeen hundred years old." 



In regard to eggs, no such examples are, we 

 believe, on record ; nevertheless, there are some 

 tribes of animals whose eggs are capable of 

 being preserved for a considerable length of 

 time, and of undergoing very severe treatment 

 without loss of their vitality. Most insects de- 

 posit their eggs sufficiently early in the summer 

 for the larvae to be hatched and attain their 

 full growth before the autumn deprives them 

 of their supply of food, and these pass the 

 winter in the pupa state. But there are some 

 which do not begin to lay until the activity of 

 vegetation has nearly ceased, and their eggs 

 remain undeveloped until the ensuing spring 

 arouses both the animal and vegetable creation 

 into life. The curious instincts which lead 

 these insects to choose secure places for the de- 

 position of their eggs, and to use other means 

 of protecting them against cold and moisture, 

 are described by Mr. Kirby; and the same 

 author points out the beautiful correspondence 

 between the temperature required for the de- 

 velopment of the buds of the plant and of the 

 larvae that prey upon them. It has been men- 

 tioned in a former article|| that the eggs of the 

 slug are capable of enduring a temperature of 

 40, and of being completely desiccated, with- 

 out losing their fertility ; and it can scarcely be 

 doubted, therefore, that these might preserve 

 their vitality like the seeds of plants for an un- 



* For several cases of this kind related on the 

 authority of Professor Graham, see Dr. Pilchard's 

 Physical History of Man, third edit. vol. i. p. 39, 

 &c. ; and for a very curious instance communicated 

 to the author of this article, see his Principles of 

 General and Comparative Physiology, p. 141. 



t See Dr. Weissenborn's papers in the Philo- 

 sophical Magazine for 1838. 



J Introduction to Uotany, p. 298. 



$ Kirhy and Spence's Entomology, vol. ii. p. 443. 



II Vol. ii. p. 402. 



limited period, if neither aroused into activity 

 nor disorganised by decomposing agents. 



It will scarcely be denied that the agents 

 which are known to destroy the vitality of 

 seeds and eggs are such as are calculated to 

 produce important changes in their structure 

 and composition, even though these be of a 

 kind inappreciable by our present means of re- 

 search. Thus most seeds are killed by a tem- 

 perature of 160, which is that at which rup- 

 ture of the vesicles of fecula takes place, and 

 the application of heat sufficient to destroy the 

 vitality of an egg coagulates its albumen. An 

 electric shock is well known to be a powerful 

 means of instantaneously extinguishing the vital 

 properties of eggs or seeds ; and although the 

 precise alterations which it effects in the struc- 

 ture or composition of their parts is not under- 

 stood, it cannot be doubted that important or- 

 ganic changes are produced by so powerful an 

 agent. Cold, in like manner, probably acts 

 injuriously on most eggs and seeds as upon 

 plants, by causing the rupture of the cells of 

 their tissues through the expansion of the con- 

 tained fluids in the act of freezing. We do 

 not mean to say that other changes are not also 

 produced by such agents, but we mention 

 these as evidences of the position with which 

 we started that vitality is not destroyed by the 

 influence of external agents without a structural 

 change of some kind being induced by their 

 operation. 



But it is not during their embryo state 

 merely, that the vital actions of living beings 

 may be suspended by the deficiency of external 

 stimuli, and yet their vitality be preserved. 

 Both the vegetable and animal kingdoms afford 

 numerous examples of such an occurrence at 

 all periods of existence, especially among their 

 lower tribes. Mosses, for instance, often ap- 

 pear completely desiccated in dry weather, and 

 seem as if dead ; whilst, on the application of 

 moisture, they revive in all their pristine beauty. 

 The curious Lycopodium of Peru exhibits this 

 torpor in a still more remarkable manner. 

 When desiccated by drought, it folds in its 

 leaves and contracts its roots so as to form a 

 ball, which, apparently quite devoid of anima- 

 tion, is driven hither and thither by the wind ; 

 as soon, however, as it reaches a moist situa- 

 tion, it sends down its roots into the soil, and 

 unfolds to the atmosphere its leaves, which, 

 from a dingy brown, speedily change to the 

 bright green of active vegetation. The rose 

 of Jericho is the subject of similar transforma- 

 tions. Instances exactly parallel are furnished 

 by the animal kingdom. The common wheel- 

 animalcule is one of the most remarkable, 

 being capable of desiccation so complete as to 

 splinter if touched with the point of a needle, 

 and still preserving its vitality so as to revive 

 when moistened.* In animals reduced to a 



* This fact has been denied by some naturalists ; 

 but the author can positively assert it from his own 

 experience. See Principles of Gen. and Comp. 

 Physiology, p. 90, note. From experiments subse- 

 quent to the one there related, he is inclined to 

 believe that of two species of Rotifer, so nearly 

 allied as to be usually considered the same, one is 

 thus revivinable, and the other not. 



