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THE POPULAR SCIENCE MONTHLY 



limbs trembling as if in a paroxysm of epi- 

 lepsy. Two persons came forward, and, 

 taking her by her arms, raised her to her 

 feet. . . . The little performance was enact- 

 ed to please the white man." 



The Life-Term of Animals and Plants.— 



Dr. August Weissman regards the life-terms 

 of animals and plants not as fixed and the 

 results of internal processes, but as modifi- 

 able according to external conditions and 

 the incidents of the struggle for existence. 

 The idea that the immediate cause of death 

 is the wearing away of the tissues does not 

 agree with the theory that the tissues are 

 undergoing constant changes of substance, 

 resulting in alteration and restoration, nor 

 with the fact that some kinds of cells go on 

 reproducing themselves indefinitely, or with 

 the other fact that some animals perish, when 

 apparently in full vigor, immediately after 

 performing the generative function. It would 

 seemingly be better to look for the cause 

 of death in the terminability of the repro- 

 ductive powers ; and we might explain the 

 difference in the possible life-terms of dif- 

 ferent species by supposing that the num- 

 ber of cell-generations which can proceed 

 from the egg-cells normally differs in each 

 species. A perishable material is provided 

 for the inevitable wear and destruction of 

 the body, and the function of unlimited in- 

 crease has been confined to a smaller num- 

 ber of cells, which we call reproductive cells. 

 We have in this and in some other facts 

 justification for supposing that the life force 

 is essentially and originally unlimited. This 

 appears to be actually the case with some 

 of the lower organisms. They may be killed 

 in various ways, it is true ; but, so long as 

 the conditions essential to life are around 

 them, they live, and bear within themselves 

 the conditions of never-ending existence- 

 The process of division by which ana mceba 

 becomes two is sometimes spoken of as 

 death and propagation, but there is no death 

 in the case. Both parts equally live, and 

 either might with equal right consider itself 

 the mother and the other as the daughter 

 body; and, if there be any transmission of 

 consciousness and individuality, it is alike 

 to both. We have no reason for supposing 

 that cither of the bodies will eventually die 

 while the other lives ; for, so far as our ob- 



servation enables us to predict, both will go 

 on dividing continuously without death tak- 

 ing place in any part. To account for the 

 loss of the property of perpetual existence 

 in the many-celled organisms, we may ob- 

 serve that a division of labor has been es- 

 tablished among the cells as their structure 

 has become more complex ; and we have 

 the life-supporting or somatic cells, and the 

 reproductive cells, the former of which per- 

 form their several functions and cease to 

 live, while the latter retain the faculty of 

 continuous division or multiplication, and 

 continue to live as the seed of offspring. 

 They could not lose these properties with- 

 out risking the extinction of the species. 

 Death could not be introduced as a normal 

 liability of one-celled organisms, because 

 the two functions are united ; but, in more 

 complex organisms where there is a divis- 

 ion of function, it is possible and exists. 

 The normal vital term of the somatic cells 

 appears to be contingent on the completion 

 of the faculty of reproduction. 



NOTES. 



T. Ec.leston, in a paper on the causes of 

 decay affecting building- stones, especially 

 mentions such causes as depend on the re- 

 moval of an ingredient by decay or decom- 

 position. He observes that dolomitic lime- 

 stones, which in some regions, in the case 

 both of the native ledges and of monuments, 

 crumble to sand, owe their disintegration 

 to the fact that they are to a large extent 

 mixtures of true dolomite and limestone ; 

 and that the limestone, the most soluble 

 portion, is dissolved and removed by perco- 

 lated carbonated waters. 



A tunnel is projected, to be bored un- 

 der Gray's Peak, in the Rocky Mountains. 

 It will be placed 4,441 feet below the sum- 

 mit of the mountain, will be 25,000 feet long, 

 and will give direct communication between 

 the valleys in the Atlantic slope and those 

 of the Pacific side, with a shortening of 

 some three hundred miles in the transmon- 

 tane distances. 



Dr. P. H. Dudley recently described to 

 the American Institute of Mining Engineers 

 two cast-iron car-wheels which a chemical 

 examination had shown to be almost precise- 

 ly the same in composition, but one of which 

 was good, while the other was nearly worth- 

 less, for its purpose. From this, it appears 

 that the value of articles of iron and steel is 

 largely dependent on other conditions than 



