385 



SCIENTIFIC SIDE-LIGHTS 



Life 



followed by some perceptible change in the 

 object. By discovering that certain things 

 shrink when touched, or fly away when ap- 

 proached, or start when a noise is made, the 

 child first roughly discriminates between the 

 living and the not-living. . . . Vegetal 

 and animal life are alike primarily recog- 

 nized by this process. The tree that puts 

 out leaves when the spring brings increase 

 of temperature, the flower which opens and 

 closes with the rising and setting of the sun, 

 the plant that droops when the soil is dry 

 and reerects itself when watered, are con- 

 sidered alive because of these induced 

 changes. . . . 



Not only, however, do we look for some 

 response when an external stimulus is ap- 

 plied to a living organism, but we expect a 

 fitness in the response. Dead as well as liv- 

 ing things display changes under certain 

 changes of condition: instance, a lump of 

 carbonate of soda that effervesces when 

 dropped into sulfuric acid; a cord that 

 contracts when wetted; a piece of bread 

 that turns brown when held near the fire. 

 But in these cases we do not see a connec- 

 tion between the changes undergone and the 

 preservation of the things that undergo 

 them. ... In vital changes, however, 

 such relations are manifest. Light being 

 necessary to vegetal life, we see in the 

 action of a plant which, when much shaded, 

 grows towards the unshaded side, an appro- 

 priateness which we should not see did it 

 grow otherwise. Evidently the proceedings 

 of a spider which rushes out when its web 

 is gently shaken and stays within when the 

 shaking is violent, conduce better to the ob- 

 tainment of food and the avoidance of dan- 

 ger than were they reversed. The fact that 

 we feel surprise when, as in the case of a 

 bird fascinated by a snake, the conduct 

 tends towards self-destruction, at once 

 shows how generally we have observed an 

 adaptation of living changes to changes in 

 surrounding circumstances. SPENCER Biol- 

 ogy, pt. i, ch. 5, p. 91. (A., 1900.) 



1881. LIFE, EXPERIMENTS FOR 

 RESTORATION OF Have I the Bright to 

 conclude from these tests that the injection 

 of blood deprived of its fibrin could suffice 

 to support irritability indefinitely and per- 

 fectly, that is to say, the local life of a mem- 

 ber separated from the body? At the least, 

 this seems very probable, for, I repeat it, . 

 there never was any sensible difference in 

 the degree of muscular irritability fifty and 

 some hours from ten minutes after death. 

 BKOWN-SEQUARD Recherches eocperimentales 

 sur les Proprieties physiologiques et les Usa- 

 ges du Sang Rouge et du Sang Noir (Journal 

 de la Physiologic de I'Homme et des Ani- 

 maux, 1858, vol. i, p. 367). (Translated 

 for Scientific Side-Lights.) 



1882. LIFE, FECUNDITY OF LOWER 

 FORMS OF Progeny Numberless Gradual 

 Diminution in Rising toward Higher Mam- 

 malia Care and Love Concentrated. When 



we examine the progeny of the lowest plants 

 we find ourselves among figures so high that 

 no microscope can count them. The Proto- 

 coccus nivalis shows its exuberant reproduc- 

 tive power by reddening the arctic landscape 

 with its offspring in a single night. When 

 we break or shake the puff-ball of the well- 

 known fungus the cloud of progeny darkens 

 the air with a smoke made up of uncount- 

 able millions of spores. Hydatina senta, 

 one of the Rotifera, propagates four times 

 in thirty-four hours, and in twelve days is 

 the parent of sixteen million young. Among 

 fish the number is still very great. The 

 herring and the cod give birth to a million 

 ova, the frog spawns eggs by the thousand, 

 and most of the creatures at and below that 

 level in a like degree. Then comes a gradual 

 change. When we pass on to the reptiles 

 the figures fall into hundreds. On reaching 

 the birds the young are to be counted by 

 tens or units. In the highest of mammals 

 the rule is one. This bringing-down of the 

 numbers is a remarkable circumstance. It 

 means the calling-in of a diffused care, to 

 focus it upon one, and concentrate it into 

 love. DRUMMOND Ascent of Man, ch. 8, p. 

 273. (J. P., 1900.) 



1883. LIFE FIGHTS OFF CORRUP- 

 TION Bacteria Cannot Thrive on Normal 

 Living Tissues. The normal living tissues 

 have an inimical effect upon bacteria. Sapro- 

 phytic bacteria of various kinds are nor- 

 mally present on exposed surfaces of skin 

 or mucous membrane. Tissues also which 

 are dead or depressed in vitality from in- 

 jury or previous disease, but which are still 

 in contact with the tissues, afford an excel- 

 lent nidus for the growth of bacteria. Still 

 these have not the power, unless specific, to 

 thrive in the normal living tissue. It has 

 been definitely shown that the blood-fluids 

 of the body have in their fresh state the 

 germicidal power . . . which prevents bac- 

 teria from flourishing in them. NEWMAN 

 Bacteria, ch. 8, p. 267. (G. P. P., 1899.) 



1 884. LIFE, FORCES OF, DESTROY 

 USELESS ORGANS White Cells (Leuco- 

 cytes) Devour Tadpole's Tail and Gills. 

 When the young frog or tadpole attains a 

 certain stage of development, and when it is 

 about to exchange its water-life for the 

 higher land existence, the fishlike tail re- 

 quires repression and demands extinction as 

 part and parcel of frog-advance. Of old we 

 believed the disappearance of the frog's tail 

 was due to a simple process of atrophy or 

 wasting away. We know better to-day. By 

 close microscopic investigation we are able 

 to see a curious work proceeding in the tad- 

 pole's appendage. It swarms with white 

 cells which have migrated into its substance 

 from the bleed- vessels. They are there for 

 a purpose, and they work with a will. They 

 are seen in the act of eating and devouring 

 the substance of their possessor. The tad- 

 pole in this sense, and through its semi-in- 

 dependent white-blood cells, is living upon 



