Criticism 

 Crystals 



SCIENTIFIC SIDE-LIGHTS 



142 



me an instrument which had all these de- 

 fects, I should think myself quite justi- 

 fied in blaming his carelessness in the 

 strongest terms, and giving him back his 

 instrument." . . . Yet I have seldom 

 met with a case so unfair as the citation of 

 this statement without any of the qualifi- 

 cations which it subsequently receives. 

 Thus, after showing that these defects 

 scarcely reveal themselves in our ordinary 

 vision some of them requiring most refined 

 methods of observation for their detection 

 Professor Helmholtz continues : " If I am 

 asked why I have spent so much time in ex- 

 plaining the imperfection of the eye, I an- 

 swer, as I said at first, that I have not done 

 so in order to depreciate the performances 

 of this wonderful organ, or to diminish our 

 admiration of its construction. It was my 

 object to make my readers understand, at 

 the outset of our inquiry, that it is not any 

 mechanical perfection of the organs of our 

 senses which secures for us such wonderfully 

 true and exact impressions of the outer 

 world. The extraordinary value of the eye 

 depends on the way in which we use it: its 

 perfection is practical, not absolute, consist- 

 ing not in the avoidance of every error, but 

 in the fact that all its defects do not pre- 

 vent its rendering us the most important 

 and varied services." This " practical per- 

 fection " he afterwards defines as " adapta- 

 tion to the wants of the organism " ; the 

 defects of the eye as an optical instrument 

 being " all so counteracted that the inexact- 

 ness of the image which results from their 

 presence very little exceeds, under ordinary 

 conditions of illumination, the limits which 

 are set to the delicacy of sensation by the 

 dimensions of the retinal cones." CARPEN- 

 TER Nature and Man, lect. 15, p. 422. (A., 

 1889.) 



701. CRITICISM ON INADEQUATE 

 DATA Geology Needs Wide Observation. 

 If it be thus unsafe, however, to calculate 

 on the depth of deposits by the altitude of 

 hills, it is quite as unsafe for the geologist, 

 who has studied a formation in one district, 

 to set himself to criticize the calculations of 

 a brother geologist by whom it has been 

 studied in a different and widely separated 

 district. A deposit in one locality may be 

 found to possess many times the thickness 

 of the same deposit in another. MILLER The 

 Old Red Sandstone, ch. 2, p. 25. (G. & L., 

 1851.) 



702. CROWS AS DISTRIBUTERS OF 



SEED Birds That Thrive on Poison-ivy. 

 Professor Barrows writes : "Crows spend only 

 the hours of darkness at the roosts, while 

 during at least twelve hours each day they 

 are dispersed far and wide over the sur- 

 rounding country, collecting and distribut- 

 ing seeds. The process of digestion at 

 least the preliminary process is very rapid 

 in crows. A caged crow, experimented on 

 during several months in the winter of 1889- 

 90, ate berries of poison-ivy with greater 



relish than any other wild fruit obtainable. 

 He swallowed about eighty berries within a 

 few moments, taking several mouthfuls of 

 sand immediately afterwards; and about 

 thirty minutes later he disgorged a large 

 pellet, consisting entirely of sand and the 

 seeds of the poison-ivy berries, the latter 

 with every shred of pulp removed by the 

 gizzardlike action of the stomach." WEED 

 Seedrtravellers, pt. ii, p. 44. (G. & Co., 1899. ) 



703. CRUCIFYING THE FLESH 



Sustained Ideal Will Control Action. The 

 strong-willed man, however, is the man who 

 hears the still small voice unflinchingly, and 

 who, when the death-bringing consideration 

 comes, looks at its face, consents to its pres- 

 ence, clings to it, affirms it, and holds it 

 fast, in spite of the host of exciting mental 

 images which rise in revolt against it and 

 would expel it from the mind. Sustained in 

 this way by a resolute effort of attention, 

 the difficult object erelong begins to call up 

 its own congeners and associates, and ends 

 by changing the disposition of the man's 

 consciousness altogether. And with his con- 

 sciousness his action changes, for the new 

 object, once stably in possession of the field 

 of his thoughts, infallibly produces its own 

 motor effects. The difficulty lies in the gain- 

 ing possession of that field. Tho the spon- 

 taneous drift of thought is all the other 

 way, the attention must be kept strained on 

 that one object until at last it grows, so as 

 to maintain itself before the mind with ease. 

 . . . The mysterious tie between the 

 thought and the motor centers next comes 

 into play, and, in a way which we cannot 

 even guess at, the obedience of the bodily 

 organs follows as a matter of course. 

 JAMES Psychology, vol. ii, ch. 26, p. 563. 

 (H. H. & Co., 1899.) 



704. CRUELTY, ANCIENT, IN 

 TREATMENT OF THE INSANE Brutality 

 Resulting from Belief in Demoniac Posses- 

 sion. It was the natural result of such 

 [medieval] views of insanity that men 

 should treat him whom they believed to have 

 a devil in him as they would have treated 

 the devil could they have had the good for- 

 tune to lay hold of him. The tortures which 

 the insane suffered* from the devils that had 

 entered into him were less than those in- 

 flicted by the devils who took charge of him. 

 When he was not put to death as a heretic 

 or a criminal, he was confined in a dungeon, 

 where he lay chained on straw; his food 

 was thrown in, and the straw raked out, 

 through the bars ; sightseers went to see 

 him, as they went to see the wild beasts, for 

 amusement; he was cowed by the whip, or 

 other instrument of punishment, and was 

 more neglected and worse treated than if he 

 had been a wild beast. Many insane per- 

 sons, too, were without doubt executed as 

 witches, or as persons who had, through 

 witchcraft, entered into compact with Satan. 

 MAUDSLEY Body and Mind, lect. 4, p. 102. 

 (A., 1898.) 



