Apbil 30, 1909] 



SCIENCE 



in 



figures in the frog's egg in the direction of the 

 force. This effect of the force is due apparently 

 to compression of the alveolar framework of the 

 egg, on one side by the fatty layer and on the 

 other by the yolk layer. 



Regeneration and Orowth in Fishes: G. G. Scott, 

 College of City of New York. 

 The caudal fin of 117 Fundulus heteroolitus of 

 sizes varying from 4.57 cm. to 9.73 cm. long was 

 removed. Fins of the younger fishes (shorter) 

 regenerated proportionately more than the older 

 (longer). In fact the curve representing the pro- 

 portional amount of regeneration in fishes of dif- 

 ferent ages (lengths) was regularly descending, 

 reminding one of curve of growth established by 

 Minot. One might conclude that regeneration 

 paralleled growth, i. e., that the power of regen- 

 eration is greater in the young. On closer exam- 

 ination we find that each fish (regardless of 

 length) regenerated about 0.6 cm. The following 

 explanation is offered: Regeneration of new fin 

 tissue is due to proliferation outwards in a linear 

 direction of new cells arising from the division 

 of cells exposed by the line of amputation. A 

 fish 5 cm. long contains same sized cells as a 

 fish 10 cm. long and the probability is that the 

 power of proliferation is about the same in the 

 cells of fishes of each size — provided that the cells 

 are at the same relative level in each case. When 

 the amputation was made the author endeavored 

 to have line of removal at same relative place in 

 all specimens. Evidence as to the similar powers 

 of regeneration residing in cells of same level 

 independent of size (age) is shown by the fact 

 that actual regeneration outwards in a linear 

 direction is same in fishes of all sizes. This indi- 

 cates that regeneration is a process independent 

 of general growth processes. It comes into play 

 under abnormal conditions. 



The Early Development of Neuroflbrillce a/nA 'Nerve 

 Function: Hansfobd M. MacCubdt, Alma Col- 

 lege, Alma, Mich. 



With the purpose to find the earliest stage at 

 which neurofibrillae may be discovered in the de- 

 veloping nerve cells and the relation between their 

 first appearance and the establishment of conduc- 

 tion paths as evidenced by the earliest normal 

 movements and reactions to external stimuli, ob- 

 servations were made on the larvse of Rana and 

 Amhlystoma. Neurofibrillae are present in the 

 earliest optic nerve fibers and in the retinal ele- 

 ments long before they can perform their regular 

 function. That they are also present in early 

 fiber tracts of the neural tube, preceding normal 



movements seems amply demonstrated, but further 

 confirmation is to be sought. It appears alto- 

 gether probable that the neurofibrillae arise prac- 

 tically contemporaneous with the outgrowth of 

 the nerve fiber. 



Regeneration in the Brittle-star Ophiucoma 

 pumila, with Reference to the Influence of the 

 Nervous System: Seegids Mobguus, Cambridge, 

 Mass. 



1. Is the presence of the nerve essential for the 

 regeneration of the arms in ihe brittle-star 

 Ophiucoma pumila? To answer this question the 

 radial nerve was injured by a red-hot needle near 

 the disc, and then the arm was cut off about the 

 middle of its length. As a control experiment 

 another arm in the same specimen was also cut 

 oil at the middle, but its radial nerve was left 

 intact. It was found that in the course of thirty 

 days the arms with radial nerve intact had all 

 regenerated normally, while those with the radial 

 nerve injured produced only a very minute stump 

 of new tissue. If, however, the arm broke off at 

 the place where the nerve was injured — as occa- 

 sionally happened soon after the operation — no 

 tissue was regenerated from such an exposed sur- 

 face, although arms in which the radial nerve was 

 intact, even in the same animal, did regenerate. 



2. What is the relation of the rate of regenera- 

 tion to the " level " at which the arms are cut off? 

 It was found that arms cut off at the base or at 

 the middle regenerate much faster than those cut 

 off at the tips. 



3. What is the relation of the rate of regenera- 

 tion to the number of arms removed? The removal 

 of different numbers of arms influences the rate of 

 regeneration of the lost arms only to a small ex- 

 tent; the rate of regeneration when four or five 

 arms are removed is somewhat greater than when 

 one, two or three arms are removed; but this 

 correlation between the degree of injury and the 

 rate of regeneration is not of the nature of a close 

 parallelism. 



Maubice ±x. Bigelow, 



Secretary 

 Teachees College, 

 Columbia Univebsity 



SOCIETIES AND ACADEMIES 



THE ANTHEOPOLOQICAl SOCEETT OF WASHINGTON 



IHE 432d regular meeting of the society was 

 held April G, 1909, President Hough in the chair. 

 The following program was presented: 

 2Vew Chapters in the History of the Goeoanut 



Palm.: Dr. O. F. Cook. 



