388 



SCIENCE 



[N. S. Vol. XXXIH. No. 845 



sitely charged colloids are brought in contact, 

 but the basic colloid may with difficulty be seen 

 as a refractive layer, which has been mistaken 

 for a poorly developed " fertilization membrane." 

 The increased permeability of the egg surface, 

 which releases the basic colloid, is one of the pre- 

 requisites to the increased oxidation of the devel- 

 oping egg, and in this way membrane formation 

 and development are induced by the same change. 

 Evidence for the Transmission of the " Wound 

 Stimulus " to Underlying Tissues and its Rela- 

 tion to Regeneration: J. F. McClendon, Cor- 

 nell University Medical College. 

 The " current of injury " produced by the nega- 

 tive electric potential of a wounded surface is 

 common to animal and plant tissues. The 

 wounded cell acts as an electric generator and a 

 current flows through neighboring cells. If a 

 current is passed through living tissue, which is 

 subsequently fixed and stained, basophile sub- 

 stances will be found displaced toward the anode. 

 In sections of tissue adjacent to a wound the 

 extent of the current is indicated by the displace- 

 ment of basophile granules. The current affects 

 first the cells in contact with the wounded cells, 

 then extends in some directions more than others, 

 lilectric currents (currents of growth) continue 

 for many days after the wound has healed. Since 

 electric currents cause sea-urchin eggs and tissue 

 cells to divide and proliferate, probably these bio- 

 electric currents constitute the so-called " forma- 

 tive stimulus " of regeneration. 

 Maturing Reagents and those Indaoing Segmenta- 

 tion in Artificial Parthenogenesis: Max With- 

 Eow MoESE, Trinity College. 

 An extended series of experiments, continued 

 throughout the summer at the Harpswell Labo- 

 ratory upon the eggs of Cerebratulus, demon- 

 strated that those reagents which induced matu- 

 ration of this egg, would not cause development 

 to proceed farther through the segmentation 

 stages and indeed evidence for an inhibiting ac- 

 tion to segmentation on the part of the solutions 

 used in causing the egg to throw off the polar 

 bodies, was obtained. The glueoside saponin, 

 dibasic acids such as oxalic, hydrochloric ana 

 tartaric acid were used successfully to mature 

 the egg, but no subsequent application of these 

 reagents caused segmentation to proceed. It was 

 found, however, that if every trace of these solu- 

 tions was removed by careful washing and the 

 eggs placed in a CO^-sea-water solution, with a 

 concentration of approximately 0.19 g. to the 

 100 g. sea water, segmentation proceeded. How- 



ever, no method was found whereby the eggs 

 could be carried beyond the later segmentation 

 stages. Loeb and others have observed this an- 

 tagonistic action of maturing and segmentation- 

 producing reagents in other forms, and in such 

 cases, as in the present one, the reactions are not 

 reversible; COj will not cause maturation. The 

 experiments were checked against temperature, 

 salinity, alkalinity and such external factors as 

 might modify results. 

 Newly Found Odonate Larvce of Special Interest 



from Costa Rica: P. P. Calvebt, University of 



Pennsylvania. 



The larva of Cora possesses two-branched man- 

 dibles, and paired ventral tracheal gills (^modi- 

 fied legs?) on abdominal segments 2-7, in addi- 

 tion to three thick caudal tracheal gills. A de- 

 tailed account has appeared in Entomological 

 News for February, 1911. 



The larva of Mecistogast&r modestus lives in 

 the rain water between the leaf-bases of arbori- 

 colous bromeliads. The remarkable increase in 

 length at transformation, from the larva meas- 

 uring 24 mm. long to the adult 82 mm. long, 

 occupying about one and a half hours, was illus- 

 trated by a series of lantern slides from life. The 

 full description will probably be published in the 

 journal quoted above. 

 The Chondrocranium of Eumeces (preliminary 



report) : Edward L. Rice, Ohio Wesleyan Uni- 

 versity. 



Preliminary comparison with chondrocranium 

 of Lacerta as described by G-aupp. For most part 

 these skulls are very similar, but with some 

 striking differences. Particularly striking is 

 enormous size in Eumeces of pars cochlearis of 

 otic capsule. This extends far down into region 

 of basal plate, displacing facialis foramen rela- 

 tively upward between the two parts of otic 

 capsule. 



In no single stage is lateral wall of temporal 

 region so complete as in Lacerta, although all the 

 same elements may be recognized in a comparison 

 of various stages, some parts being in regression 

 while others are progressively developing. In 

 earliest stages taenia parietalis media extends 

 vipward and backward to unite with taenia mar- 

 ginalis, thus dividing fenestra prootica into upper 

 and lower portions, latter furnishing exit for 

 trigeminal nerve. 



Cartilage of interorbital septum continuous in 

 younger specimens; progressively fenestrated in 

 later stages. 



Nasal capsule in general less complete than in 



