184 Tin: Erolut'iun of Mbid. 



labor among them, with a consequent exaggeration of some 

 amoeboid power in one set, and another in another. No new 

 qiialities were added. It would be contrary to the simplest 

 implications of tha doctrine of evolution to deny a psycho- 

 logical parallelism to this physiological fact, wherever and 

 whenever the first traces of mind can be seen. For a few 

 years i)ast there has been a strong tendency among some 

 evolutionists to look upon consciousness as an unnecessary 

 accompaniment of automatons like men and animals.* It 

 does not seem to strike such reasoners that the fact of its 

 slow selective improvement proves its utility.! Reflex ac- 

 tion is their universal solvent of all physiological difficulties, 

 but they seldom pause to inquire as to what reflex action 

 itself may be. In the simplest forms of life facts appear 

 that transcend all purely mechanical explanations. Machines 

 make neither judgments nor choices. An amoeba in search 

 of food pursues no haphazard methods, but makes most care- 

 ful selections of the kind it wants. It will send out its 

 pseudopodia, catch, swallow and digest a struggling infuso- 

 rium $ or other nutritious game ; but a mere touch of a grain 

 of sand satisfles it as to its character, when it thrusts it 

 from it in a way that plainly says, " That's not good." § 

 Oxygen-coiipuming bacteria will cluster around grains of 

 chlorophyll if exposed to direct sunlight, but yjay no atten- 

 tion to them in the shade or darkness. They know when 

 the oxygen is being given off. Engelmann is able to detect 

 the presence of the trillionth part of a milligram of oxygen 

 by the behavior of bacteria. || Infusoria guide themselves 

 in hunting their food with apparently as much precision as 

 fish. They avoid obstacles, and sometimes undertake to 

 move them out of the way. They carefully examine float- 

 ing particles to determine their edibility. They reject the 

 innutritions, and take the nutritious. IT Hunter-ciliates, 

 after destroying their prey, search right and left in every 

 direction for it. After hunting some time, if they fail to 

 find the shattered victim, a new race is begun for other 

 l)abulum.** Didinium will attack Paramoecium aurelia, but 

 not Paramoecium bursaria, thus showing a knowledge of the 

 distinction of species, ft Troops of Bodo-caudatus will attack 

 animalculae many times their own size. A Colpod thus at- 



*Pop. Scl. Mon., Vol.5, pp. 722-734 (Huxley). 



t Miud, Vol. 4, pp. 3-6 (James). % Pop. Sci. Moii., Vol. G, p. 758. 



SMcCormack's Binet's Psychic Life of Micro-Orgaiiisuis, p. 41. 



llOp. Cit.pp. 32, 33. Hlbid, p. 46. ** Ibid, p. 48. tt Tbid, p. 53. 



