SCIENTIFIC SIDE-LIGHTS 



Action 

 Activity 



Rhizopod or Ameba. Where there are no 

 distinctions of structure there are no dis- 

 tinctions of function. A rhizopod (e. g., the 

 ameba) will serve as an illustration. From 

 the outside of this creature, which has not 

 even a limiting membrane, there are pro- 

 truded numerous processes. Originating 

 from any point of the surface, each of these 

 may contract again and disappear, or it may 

 touch some fragment of nutriment which it 

 draws with it, when contracting, into the 

 general mass thus serving as hand and 

 mouth; or it may come in contact with its 

 fellow-processes at a distance from the body 

 and become confluent with them; or it may 

 attach itself to an adjacent fixed object, and 

 help by its contraction to draw the body into 

 a new position. In brief, this speck of ani- 

 mated jelly is at once all stomach, all skin, 

 all mouth, all limb, and doubtless, too, all 

 lung. SPENCER Biology, pt. ii, ch. 1, p. 200. 

 (A., 1900.) 



33. ACTIVITY OF MIND Increases 

 Flow of Blood to Brain. The brain itself is 

 an excessively vascular organ, a sponge full 

 of blood, in fact; and [one] of Mosso's in- 

 ventions showed that when less blood went 

 to the arms, more went to the head. The 

 subject to be observed lay on a delicately 

 balanced table which could tip downward 

 either at the head or at the foot if the 

 weight of either end were increased. The 

 moment emotional or intellectual activity 

 began in the subject, down went the balance 

 at the head-end, in consequence of the redis- 

 tribution of blood in his system. But the 

 best proof of the immediate afflux of blood 

 to the brain during mental activity is due 

 to Mosso's observations on three persona 

 whose brain had been laid bare by lesion of 

 the skull. By means of apparatus . . . 

 this physiologist was enabled to let the 

 brain-pulse record itself directly by a tra- 

 cing. The intra-cranial blood-pressure rose 

 immediately whenever the subject was 

 spoken to, or when he began to think active- 

 ly, as in solving a problem in mental arith- 

 metic. Mosso gives in his work a large num- 

 ber of reproductions of tracings which show 

 the instantaneity of the change of blood-sup- 

 ply, whenever the mental activity was quick- 

 ened by any cause whatever, intellectual or 

 emotional. He relates of his female subject 

 that one day while tracing her brain-pulse 

 he observed a sudden rise with no apparent 

 outer or inner cause. She, however, confessed 

 to him afterwards that at that moment she 

 had caught sight of a skull on top of a piece 

 of furniture in the room, and that this had 

 given her a slight emotion. JAMES Psychol- 

 ogy, vol. i, ch. 3, p. 98. (H. H. & Co., 1899.) 



34. ACTIVITY OF SOLAR FORCES 



Turmoil behind Beneficence Productive 

 Forces Not Always Beautiful in Operation. 

 The furnace [the sun] whose fires main- 

 tain the life of the solar system is not 

 merely aglow with intense light and heat, 

 but is in a state of fierce turmoil. The 



most tremendous conflagrations ever wit- 

 nessed upon our earth great fires, by which 

 whole cities have been destroyed serve to 

 suggest something of what is going on upon 

 the sun, only that all the processes of such 

 catastrophes must be supposed to be inten- 

 sified a million-fold. As in great fires, there 

 is a constant roar and tumult produced by 

 the rush of air currents which the fire itself 

 has generated, so in every part of the sun, 

 on every square yard of that enormous sur- 

 face, the most hideous uproar must prevail 

 as fierce cyclonic storms, bred__by solar fires, 

 rush with inconceivable velocity over the 

 flaming surface. In the most tremendous 

 storms known upon earth the wind does not 

 travel a hundred miles per hour, and the 

 winds which rage amid the flames of a con- 

 flagration are of slow motion compared with 

 true hurricanes; but the cyclonic storms 

 which stir the fiery breath of the solar 

 flames career often with the inconceivable 

 velocity of more than a hundred miles in 

 every second of time. PROCTOR Expanse of 

 Heaven, ch. 2, p. 17. (L. G. & Co., 1897.) 



35. ACTIVITY OF SWALLOWS Use- 

 fulness as Insectivorous Birds. Swallows 

 are eminently insectivorous. The tree- 

 swallow is known to feed on bayberries 

 when its usual fare is wanting, but, with 

 this exception, it is doubtful if any but 

 insect food passes a swallow's bill from one 

 year's end to another. Recalling now the 

 activity of swallows, which both necessi- 

 tates a large supply of food and procures it, 

 we must realize that these birds are incal- 

 culably beneficial. CHAPMAN Bird Life 

 ch. 7, p. 212. (A., 1900.) 



36. ACTIVITY, VOLCANIC, ON THE 



MOON Conflicting Testimony Explained. 

 In the Sea of JXectar we see a small crater, 

 of which the diameter measures about 

 6,000 meters (about 3% miles), rising iso- 

 lated in the midst of a vast plain. Well, 

 this crater is sometimes visible and some- 

 times invisible. From 1830 to 1837 it was 

 certainly invisible, for two observers abso- 

 lutely strangers to each other, Madler and 

 Lohrmann, have minutely analyzed, de- 

 scribed, and drawn this lunar country, and 

 saw, very near the position it occupies, de- 

 tails of the ground very much less impor- 

 tant than itself, without having the least 

 suspicion [of it]. In 1842-43 Schmidt ob- 

 served this same country without perceiving 

 it. He saw it for the first time in 1851. It may 

 be distinguished very well in a direct photo- 

 graph by Rutherfurd taken in 1865. But in 

 1875 the English selenographer Neison ex- 

 amined, drew, and described this same place, 

 with details the most minute and measures 

 the most precise, without perceiving any 

 trace of the volcano. Since then it has been 

 seen again several times. It seems that the 

 most simple explanation to give of these 

 changes of visibility would be to admit that 

 this volcano now and then emits smoke or 

 vapors which remain for some time sus- 



