509 



SCIENTIFIC SIDE-LIGHTS 



Painting 

 Parsimony 



(32.8 feet) ! Well, it is in this width that 

 the annual motion of a star is performed. 

 The telescope magnifies it, of course; with- 

 out this it would be absolutely impercepti- 

 ble; but how easily it can be concealed by 

 the imperceptible motions of the telescope, 

 by the influences of temperature, by refrac- 

 tion, precession, nutation, aberration, and 

 by the proper motion of the star itself 

 in space! All these united influences 

 amount to several seconds, and are them- 

 selves subject to some uncertainties, and 

 instrumental errors must still be added to 

 them. How, then, shall we extricate trust- 

 worthy indications of the minute displace- 

 ment due to the effect of the earth's motion ? 

 Astronomers have, however, succeeded in 

 doing so for some stars. FLAMMARION 

 Popular Astronomy, bk. v, ch. 5, p. 596. 

 (A.) 



2504. PARASITE, DEFINITION OF 

 Food and Shelter at Second Hand. In gen- 

 eral, we term every living creature a para- 

 site, in the widest sense, that takes shelter 

 and food within a living creature of another 

 sort. The shelter may be temporary or per- 

 manent, and the food may either be derived 

 directly from the fluids or the tissues of the 

 host, or from his gains, or even from his 

 secretions or excretions, and offal. The only 

 requisite for being a parasite is that by na- 

 ture it should be assigned to such a host 

 that it must be unable to maintain existence 

 without such an organism to entertain it, 

 and it is immaterial whether the parasite 

 is inconvenient or not to the host, or whether 

 he causes any visible injury or not, or even 

 whether he may be useful in any respect. 

 HELLER Die Schmarotzer, mit l)esonderer Be- 

 rucksichtigung der filr den Menschen wich- 

 tigen, p. 3. (Translated for Scientific Side- 

 Lights.) 



2505. PARASITE, INJURY TO SILK- 

 WORM FROM If, in 1870, any one had af- 

 firmed that a miserable little insect from 

 across the water were going to cause to 

 France an injury of an importance pecuni- 

 arily equal to, in fact even greater than, that 

 incurred by the war indemnity paid to Ger- 

 many, people would have protested against 

 such a prophecy as pessimistic altogether 

 nonsensical. Nevertheless, it is true, or at 

 least will come true. BEAULIEU, quoted, 

 p. 204, in HELLER'S Die Schmarotzer. 

 (Translated for Scientific Side-Lights.) 



2506. PARASITISM A CAUSE OF DE- 

 GENERACY Many groups of animals con- 

 tain certain genera, families, or even whole 

 orders, which live at the expense of other 

 animals, feeding on their blood or tissues, 

 yet not killing them after the manner of 

 beasts of prey. Such are the parasites, some 

 of which only seek their unwilling host 

 when impelled by hunger, and leave it as 

 soon as they are satisfied, while others take 

 up their abode in or upon it, only to be 

 driven thence by its death. The great group 



of worms includes very many parasites, and 

 they are almost as numerous among the 

 Crustacea. Most crustaceans are free-swim- 

 ming or actively running inhabitants of the 

 water, especially of the sea, and their food 

 is partly of a vegetable nature and partly 

 consists of living or dead animals ; but near- 

 ly every order includes some parasitic form, 

 in which the effects of disuse resulting from 

 parasitism are plainly traceable. WEIS- 

 MANN Heredity, vol. ii, p. 10. (Cl. P., 1892.) 



25O7. Inaction Entails 



Loss of -Function Idleness Ends in Degra- 

 dation. That something of the lower na- 

 ture often commingles with higher things 

 is, unfortunately, a fact of life that needs 

 no new illustration. Mistletoe is a " para- 

 site " on apple and oak, and parasites 

 belong to the groundlings among life's chil- 

 dren. There is no nobility in the charac- 

 ter of animal or plant which attaches 

 itself to another living being, either as 

 a lodger or a boarder, or in the double ca- 

 pacity of an unbidden guest. Plant morals, 

 like animal morals, are often of the grossly 

 utilitarian type. If a living being is cun- 

 ning enough to take life easy by absorbing 

 the food which another child of life prepares 

 for its own use, the parasite doubtless bene- 

 fits by its assumption of the role of unwel- 

 come guest. . . . But there is a stern 

 decree of that implacable female, Madre 

 Natura, which declares that parasitism in- 

 cludes the lowering of the form which sac- 

 rifices its vital independence to luxurious 

 comfort and inglorious ease. In animals, 

 legs, stomachs, eyes, and other belongings 

 are swept away when the parasite, attaching 

 itself to another animal, is found to have 

 no use for the organs of free and normal 

 existence. This is the penalty of parasitism 

 everywhere degradation and backsliding in 

 the vital scale. ANDREW WILSON Glimpses 

 of Nature, ch. 21, p. 69. (Hum., 1892.) 



25O8. PARSIMONY IN CONSCIOUS- 

 NESS Perceptions Needless to Notice Become 

 Unconscious The Goal Becomes All. It is 

 a general principle in psychology that con- 

 sciousness deserts all processes where it can 

 no longer be of use. The tendency of con- 

 sciousness to a minimum of complication is 

 in fact a dominating law. The law of par- 

 simony in logic is only its best known cause. 

 We grow unconscious of every feeling which 

 is useless as a sign to lead us to our end. 

 . . . So in acquiring any art or voluntary 

 function. The marksman ends by thinking 

 only of the exact position of the goal, the 

 singer only of the perfect sound, the balancer 

 only of the point of the pole whose oscilla- 

 tions he must counteract. The associated 

 mechanism has become so perfect in all 

 these persons that each variation in the 

 thought of the end is functionally corre- 

 lated with the one movement fitted to bring 

 the latter about. Whilst they were tyros 

 they thought of their means as well as their 

 end: the marksman of the position of his 



