400 



SCIENCE 



[Vol. IV., No. 90. 



by Weismann's, partially liberates himself 

 from the confusion as to individuality, and 

 propounds the hypothesis of a lehensfevment , 

 which he supposes to be continually renewed 

 in protozoa, which he thus assumes to be po- 

 tentially immortal. He also fails to recognize 

 that the true question is, not whether single 

 protozoa die, but whether they form senescent 

 cycles. In this error he is followed by Cholo- 

 dowsky, 2 who also admits that natural death 

 is restricted to the multicellular animals, but 

 overlooks what would be its only possible homo- 

 logue among protozoa. 



Goette seems to me to have made a distinct 

 advance beyond his predecessors, for he has 

 attempted 3 to show that there is a death com- 

 mon to all organisms. Especially is his conclu- 

 sion that death and reproduction are intimately 

 connected to be noted as important ; but his 

 thought appears to me often vague and ob- 

 scure, and to many of his views I can by no 

 means assent. I have just asserted that death 

 and reproduction arc intimately connected. 

 Now, if my theory is correct, it is evident 

 that each cycle, before it is completely ex- 

 hausted, must produce the initials of new 

 cycles : hence the connection in time between 

 maturity, or the approach of death, and sexual 

 reproduction. By speculation upon the few 

 available facts, I have reached the following 

 hypothesis. Originally each cell of a cycle 

 was a distinct individual ; the exhaustion of the 

 last cells of the cycle caused them to become 

 sexual bodies and to conjugate ; conjugation 

 renews the power of division in the conjugated 

 individuals, and therewith a new cycle is be- 

 gun. Subsequently multicellular animals were 

 evolved, and in these the same phenomena 

 recur ; but some of the cells have become spe- 

 cially organized, and thereby incapable of as- 

 suming the sexual state : hence, when the end 

 of the cycle approaches, only a few cells be- 

 come sexual, and the animal (or plant) is ma- 

 ture. The higher organisms become sexually 

 active only after having grown for a consider- 

 able period, because they still preserve the 

 primitive relation. Senilit}' is the auslosende 

 reiz of sexual reproduction. I hope to dis- 

 cuss the matter fully in a memoir which I am 

 now preparing for the press. 



It is evident, that, according to this hypothe- 

 sis, sexual reproduction depends on the ex- 

 haustion of the cells. There are many facts 

 known to confirm this view. Thus among men 



* O. Biitschli (1882), Godanken ueber leben und tod, Zool. 

 anzeiger, v. 64-67. 



•-' N. Cholodowsky (1882), Tod und unsterblichkeit in der 

 tbierwelt, Zool. anzeiger, v. 264, 265. • 



8 A. Goette (1883), Ueber den ureprung des todes (Hamburg 

 and Leipzig, 1883, 8°), p. 81. 



the reproductive period begins sooner when 

 they are ill fed. Among many of the lower 

 plants, reproduction is induced by defective 

 nutrition. I believe that nutrition and repro- 

 duction are, indeed, opposed to one another, 

 but bj' no means in the sense taken by Carpen- 

 ter 1 and Spencer. 2 While I consider that the 

 impaired nutrition causes the effort to repro- 

 duce, they believe that reproduction is opposed 

 to nutrition, constituting a tax which with- 

 draws just so much from the parent. Un- 

 doubtedly, in those cases where the parent, in 

 consequence of a secondarj" addition to the 

 office of genesis, has to supply food to its } r oung, 

 reproduction may detract from growth, but, 

 even in such cases, only sometimes. Carpenter 

 and Spencer's whole argument rests upon the 

 assumption that the power of assimilation is 

 only just equal, or about equal, to the demands 

 of the parent. It is, however, perfectly well 

 known that the reverse is true, and that there 

 is in most organisms a large surplus of assimi- 

 lation possible, which is used whenever the 

 functions demand it : hence in most cases the 

 secondaiy taxes of reproduction can be wholly 

 or mainly paid without calling on the growth 

 capital of the parent. Spencer's a priori ar- 

 gumentation I consider superficial : it has led 

 him to an exaggerated idea of an opposition 

 which exists in nature, but is not general. 

 Moreover, Spencer has mistaken the cart for 

 the horse : animals do not stop growing be- 

 cause the} T begin to reproduce, but they begin 

 to reproduce because they stop growing ; or, 

 more strictly speaking, both events are due to 

 one cause, — senescence. 



It will be seen, upon reviewing the preceding 

 paragraphs, that the views I advocate are op- 

 posed to all the other opinions upon the nature 

 of death which have been noticed above. In 

 a memoir I am now at work upon, I hope to 

 array a large number of observations to defend 

 the theoiy outlined in this essaj". 



C. S. MlNOT. 



AMERICAN APPLIANCES FOR DEEP- 

 SEA INVESTIGATION. 



The wire dredge-rope. 

 It was a revolution in deep-sea dredging 

 methods, when the cumbersome hempen rope 

 was discarded for one of wire, measuring 

 scarcely more than one-third the same diame- 

 ter, stronger, more durable, and less expensive. 

 The introduction of wire-rope will not affect 



1 William B. Carpenter, Principles of physiology, general 

 and comparative (3d ed., 1851), p. 592. 



2 II. Spencer, The principles of biology, vol. ii. pt. vi. 



