Maech 19, 1915] 



SCIENCE 



439 



The neuro-museular complex may be regarded 

 as standing at a threshold of organization. 

 Morphologically standing at the level of a tissue, 

 it exhibits the physiological definiteness and dif- 

 ferentiation which characterize an organ. Thus, 

 in a sense, function anticipates structure. 



(Based upon a paper now in press in Archil) 

 fur EntwicTcelungsmechamlc der Organismen.) 



The Form of the Stomach in Embryos of the Cat, 

 Albino Sat, Pig and Sheep: Chester H. 

 Heusee. 



Utero-gestation in the Sheep-nosed Shark, Scolio- 



don Terranovce: E. W. Gudgee. 



In a 37i-inch specimen with a girth of 13J 

 inches taken at Tortugas, Florida, the left ovary 

 was twice as long as the non-functional left lobe, 

 while the ovidueal apparatus was paired, sym- 

 metrical, and had both sides functional. The eggs, 

 each enclosed in a thin yellow shell with its long 

 pointed ends curiously folded and plaited, lay in 

 crypt-like lateral "nests" formed in the mucous 

 lining of the uteri. The structure of the uterus 

 and the formation of the "nests," with the re- 

 lation thereto of the curious shells, were described 

 and illustrated, as were also the young and their 

 connection with the yolk and finally with the 

 uterine wall. In all respects the eggs and their 

 shells together with the uteri containing them are 

 in close parallel with similar structures in the 

 bonnet-head shark, Sphyrna tiburo, reported on by 

 the speaker at the Princeton meeting of the so- 

 ciety in 1911. 



An article giving all the data at hand and il- 

 lustrated by photographs will appear later in 

 "Papers from the Tortugas Laboratory" of the 

 Carnegie Institution of Washington. 



Experimentally Fused Larvce, with Special Refer- 

 ence to Changes in Polarity, Symmetry, Syn- 

 chronity, Etc.: A. J. Goldparb. 



Experiments in Cleavage: T. S. Painter. (Intro- 

 duced by B. G. Harrison.) 



Cytology 



A Study of the Maturation Period in the Ameri- 



ca/n, and European Molecrichets : F. Payne. 



Regenerative Potencies of Dissociated Cells of 

 Sydromedusce : Charles W. Hargitt. 

 The paper describes experiments made at the 

 Zoological Station, Naples, several years ago. 

 About a dozen species of hydroids, and one spe- 

 cies of medusa were experimented on, and with 



results which in the main confirm those of H. V. 

 Wilson, published since my own were made. The 

 paper also briefly reviews a series of similar ex- 

 periments made by DeMorgan and Drew.i These 

 latter experiments are the immediate occasion for 

 giving publicity to my own work, as they appear 

 to imply some doubt as to the conclusiveness of 

 Wilson's work. Their experiments were made 

 upon two species of Antennularia, and while serv- 

 ing to confirm earlier phases of those of Wilson 

 they never gave rise to new hydranths. The au- 

 thors declare "our experiments have resulted in 

 the production of masses that are certainly ab- 

 normal and pathological, but nevertheless we 

 would submit that the segregation and rearrange- 

 ment of the cells after' isolation, and the consid- 

 erably long duration of life of the tumor-like 

 masses to which they give rise, are facts of con- 

 siderable theoretical interest. ' ' 



The paper will show that the assumption as to 

 the abnormality and pathological conditions ap- 

 parent are not warranted by the more extended 

 knowledge of facts from these and other sources. 

 Indeed, many facts concerning the behavior of 

 these organisms in development and regeneration 

 seem to prove that fundamentally there is neither 

 abnormality nor pathological process involved. 



Microdissection Studies on the Physical Proper- 

 ties and Behavior of Cell Structures, Especially 

 in Orthopteran Spermatogenesis : ■'Robert Cham- 

 bers, Jr. 



Cells studied were of Orthopteran gonads, plant- 

 root tips and pancreas of frog. Fresh material 

 corroborates in many interesting details nuclear 

 structures observed in fixed material. Mitochon- 

 dria and the cytoplasm, however, largely show 

 artifacts with fixatives. 



Puncture of a cell by a needle generally causes 

 irreparable injury. Slight injury hastens the 

 normal reversible changes in the physical states of 

 the colloids in the cell, but soon transforms them 

 to an abnormal condition which leads to death. 

 Injury to the cell is followed by swelling ac- 

 companied by an increased imbibition of water. 

 Physiological salt solutions are more or less in- 

 jurious to cells normally bathed in organic fluids. 

 A tension exists in the cell during division 

 which is lost when any part of the cell is torn. 

 Janus green (Hoeehst) stains mitochondria 

 rapidly. In the nucleus it is reduced to safranin, 

 which kills the cell. 



1 Jour. Marine Biol. Assoc, Plymouth, October, 

 1914. 



