trength 



truggle 



SCIENTIFIC SIDE-LIGHTS 



658 



3252. STRENGTH OF STRUCTURE 

 ADAPTED TO RESISTANCE Shells of 

 Plymouth Breakwater Weakest against 

 Least Exposure. The same species of mol- 

 lusk lias often a shell comparatively weak 

 and thin, or a shell comparatively ro- 

 bust and strong, according as it lies in 

 tranquil or in stormy water. The shell 

 which is much exposed needs to be stronger 

 than the shell which is less exposed. But 

 it is obvious that the mere fact of the 

 need cannot supply the thing needed, un- 

 less by the adjustment of some machin- 

 ery for the purpose. How the vital forces 

 of the mollusk can thus be made to work 

 to order, under a change of external condi- 

 tions, we do not know. But we do know, 

 as a matter of fact, that the shell is thick- 

 ened and strengthened according as it needs 

 resisting power. This result does not ap- 

 pear to arise from any difference in the 

 amount of lime held in solution in the 

 water, but from some power in the secreting 

 organs of the animal to appropriate more or 

 less of it according to its own need. The 

 effects of this power are seen where there 

 is no difference of condition except difference 

 of exposure. It is said that they are ob- 

 servable, for example, in the shells which 

 lie on the different sides of Plymouth break- 

 water the sheltered side and the exposed 

 side. The same power of adaptation is seen 

 in many other forms. Trees which are most 

 exposed to the blast are the most strongly 

 anchored in the soil. Limbs which are the 

 most used are the most developed. Organs 

 which are in constant use are strengthened, 

 whilst organs in habitual disuse have a ten- 

 dency to become weaker. ARGYLL Reign of 

 Law, ch. 5, p. 128. (Burt.) 



3253. STRENGTH, SURPRISING 



Physical Effect of Emotion. Of the almost 

 superhuman strength and agility with which 

 the body seems endowed, when the whole 

 energy is concentrated upon some nervo- 

 muscular effort, especially under the in- 

 fluence of an overpowering emotion, the 

 following remarkable example has been 

 communicated to the writer by a gentleman 

 on whom he can place full reliance, and who 

 was personally cognizant of the fact: An 

 old cook-maid, tottering with age, having 

 heard an alarm of fire, seized an enor- 

 mous box containing her whole property, 

 and ran downstairs with it as easily as she 

 would have carried a dish of meat. After 

 the fire had been extinguished she could not 

 lift the box a hair's breadth from the ground, 

 and it required two men to convey it up- 

 stairs again. CARPENTER Mental Physiol- 

 ogy, ch. 7, p. 328. (A., 1900.) 



3254. STRENGTH UNDERMINED 



White Ants Eat Out the Substance of 

 Timber from Within. Either from the de- 

 sire to remain undiscovered [according to 

 Biichner], or from their liking for darkness, 

 they [the white ants] have the remarkable 

 habit of destroying and gnawing everything 



from within outwards, and of leaving the 

 outside shell standing, so that from the out- 

 side appearance the dangerous state of the 

 inside is not perceptible. If, for instance, 

 they have destroyed a table or other piece of 

 household furniture, in which they always 

 manage from the ground upwards to hit ex- 

 actly the places on which the feet of the ar- 

 ticle rest, the table looks perfectly uninjured 

 outside, and people are quite astonished when 

 it breaks down under the slightest pressure. 

 The whole inside is eaten away, and only 

 the thinnest shell is left standing. If fruits 

 are lying on the table they also are eaten 

 out from the exact spot on which they rest 

 on the surface of the table. In similar fash- 

 ion things consisting wholly of wood, such 

 as wooden ships, trees, etc., are destroyed 

 by them so that they finally break in with- 

 out any one having noticed the mischief. 

 ROMANES Animal Intelligence, ch. 5, p. 201. 

 (A., 1899.) 



3255. STRESS OF EMOTION MAKES 

 PAST SEEM DISTANT A Great Sorrow 

 Quickly Seems Old. Our representation of 

 the position of a given event in the past 

 is ... determined by the movement of 

 imagination in going back to it from the 

 present. And this is the same thing as to 

 say that it depends on our retrospective 

 sense of the intervening space. That is 

 to say, the sense of distance in time, as 

 in space, is the recognition of a term to 

 a movement. ... A very recent event, 

 bringing with it a deep mental shock and a 

 rapid stirring of wide tracts of feeling and 

 thought, may get to look old in a marvelous- 

 ly short space of time. An announcement 

 of the loss of a dear friend, when sudden 

 and deeply agitating, will seem remote even 

 after an hour of such intense emotional 

 experience. SULLY Illusions, ch. 10, p. 254. 

 (A., 1897.) 



3256. STRIFE IN NATURE The 



Struggle for Existence Parasites Have 

 Brought Famine to Man. In thus obtain- 

 ing possession of the earth by conquest [of 

 animals], and defending our acquisitions by 

 force, we exercise no exclusive prerogative. 

 Every species which has spread itself from 

 a small point over a wide area must, in 

 like manner, have marked its progress by 

 the diminution or the entire extirpation of 

 some other, and must maintain its ground 

 by a successful struggle against the en- 

 croachments of other plants and animals. 

 That minute parasitic plant, called " the 

 rust " in wheat, has, like the Hessian fly, 

 the locust, and the aphis, caused famines 

 ere now amongst the " lords of the cre- 

 ation." The most insignificant and diminu- 

 tive species, whether in the animal or vege- 

 table kingdom, have each slaughtered their 

 thousands, as they disseminated themselves 

 over the globe, as well as the lion, when 

 first it spread itself over the tropical regions 

 of Africa. LYELL Principles of Geology, bk. 

 iii, ch. 41, p. 688. (A., 1854.) 



