496 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912. 



show that living beings are governed by laws identical with those 

 which govern inanimate matter. The more we study the manifes- 

 tations of life the more we become convinced of the truth of this 

 statement and the less we are disposed to call in the aid of a special 

 and unknown form of energy to explain those manifestations. 



PHENOMENA INDICATIVE OF LIFE MOVEMENT. 



The most obvious manifestation of life is "spontaneous" move- 

 ment. We see a man, a dog, a bird move, and we know that they 

 are alive. We place a drop of pond water under the microscope, and 

 see numberless particles rapidly moving within it; we affirm that it 

 swarms with "life." We notice a small mass of clear shme changing 

 its shape, tllro^ving out projections of its structureless substance, 

 creeping from one part of the field of the microscope to another. We 

 recognize that the slime is living; we give it a name — Amoeha Umax — 

 the slug amoeba. We observe similar movements in individual cells 

 of our own body; in the white corpuscles of our blood, in connective 

 tissue cells, in growmg nerve cells, in young cells everywhere. We 

 denote the similarity between these movements and those of the 

 amoeba by employing the descriptive term "amoeboid" for both. 

 We regard such movements as indicative of the possession of "hfe"; 

 nothmg seems more justifiable than such an inference. 



But physicists * show us movements of a precisely similar character 

 in substances which no one by any stretch of imagination can regard 

 as Hving; movements of oil drops, of organic and inorganic mixtures, 

 even of mercury globules, which are indistinguishable in their char- 

 acter from those of the living organisms we have been studying: 

 movements which can only be described by the same term amoeboid, 

 yet obviously produced as the result of purely physical and chemical 

 reactions causing changes in surface tension of the fluids under exam- 

 ination.- It is therefore certain that such movements are not spe- 

 cifically "vital," that then presence does not necessarily denote "life." 

 And when we investigate closely, even such active movements as 

 those of a A-ibratile cilium or a phenomenon so intimately identified 

 with life as the contraction of a muscle, we fuid that these present so 

 many analogies with amoeboid movements as to render it certain 

 that they are fundamentally of the same character and produced in 

 much the same manner.^ Nor can we for a moment doubt that the 



» G. Quincke, Annal. d. Physik u. Chem., 1870 and 1888. 



' The causation not only of movements but of various other manifestations of life by alterations in surface 

 tension of living substance Is ably dealt with by A. B. Macallum in a recent article in Asher and Spiro's 

 Ergebnisse der Physiologic, 1911. Macallum has described an accumulation of potassium salts at the 

 more active surfaces of the protoplasm of many cells, and correlates this with the production of cell activity 

 by the effect of such accumulation upon the surface tension. The literature of the subject will be found in 

 this article. 



' G. F. Fitzgerald (Brit. Assoc. Reports, 1898, and Scient. Trans. Roy. Dublin Society, 1898) arrived at 

 this conclusion with regard to muscle from purely physical considerations. 



