Attqust 2S, lOOS] 



SCIENCE 



287 



Heilprin ("Mt. Pelee and the tragedy of 

 Martinique ") mentions severe earthquakes in 

 Gnatamala, April IS (B) and September 26 

 (J) ; Finland, April 10-11, and Lalce Baikal, 

 April 12 U); Caucasus, April 17 (B). 



Finally, to turn from the past to the pres- 

 ent and future, I have plotted the curve for 

 190S — a clean page upon -which the reader 

 may make liis own observations. The Chilapa 

 (Mexico) earthqualce and the sudden disap- 

 pearance of the lake in Oregon will be found 

 to correspond well with the curve. The earth- 

 quake registered by the Washington seis- 

 mograph May 15 and calculated to have oc- 

 curred at a point about 3,000 miles distant 

 should, if our conclusions are correct, be of 

 volcanic origin, corresponding, as it does, with 

 a luni-solar maximum. From the condition 

 of Etna during 1907 the writer freely pre- 

 dicted an eruption during the present year 

 and, with the aid of the curve, localized it to 

 the spring- and summer months. At the time 

 of writing (May) news has come of the initia- 

 tion of the eruption and it will be interesting 

 to follow its course in connection with the 

 curve and to see if its crises and culminations 

 correspond with the maxima of June 15, July 

 li or August 13. 



In conclusion the writer desires to state 

 that he fully realizes the crudity and incom- 

 pleteness at present of this working theory, 

 and his object in bringing it forward at this 

 time, instead of elaborating it by further study 

 and observation, is to stimulate the criticism 

 of others in order that the truth may be the 

 more rapidly advanced. The importance of 

 being able to foreknow the dates in each 

 month when volcanic and seismic manifesta- 

 tions will take place is too obvious to require 

 emphasizing and these data, in connection 

 with research work localized at volcanic and 

 seismic centers, should carry us a long step 

 forward along the line of definitely predict- 

 ing all such events. During the past two 

 years the writer has often made use of this 

 foreknowledge in planning his visits to vol- 

 canoes at interesting times and in absenting 

 himself for preparation work during the in- 



tervals of quiet, and it was principally by 

 means of tlie luni-solar curve that the crisis 

 in the eruption of Stromboli last year was- 

 shown to have already occurred when warships 

 had been sent with a view to deporting the' 

 4,000 inhabitants. A resort to this extreme 

 measure was thus rendered unnecessary and' 

 this application of our working theory forms 

 a good example of its practical utility. 



The present activity of Etna should form a 

 good control and will undoubtedly be of aid 

 in the computing of future curves. 



Frank A. Ferret 



THE LOCATION OF EMBRYO-FORMING REGIONS IN 

 THE EGG 



The relation between the visible substances 

 of the egg (nucleus, yolk, pigment, oil, etc.) 

 and the regions of organ-formation has at- 

 tracted the critical attention of embryologists 

 in recent years. No little diversity of opinion 

 has been expressed as to the role played by 

 these substances; whether they represent 

 organ-forming regions, or whether they are 

 only indicia, at most, of more profound 

 changes, is at present the central point of 

 dispute. The separation and stratification of 

 many of these substances by means of the 

 centrifuge has made possible the further 

 analysis of the problem. I wish to put on 

 record here the results of an experiment that . 

 bears very directly on the interpretation of the 

 location of organ-forming regions of the egg 

 of Arhacia. 



As first shown by Lyon, the egg of the sea- 

 urchin may be stratified into four regions by 

 means of the centrifuge. The nucleus is 

 driven into the axis of rotation (secondary 

 egg-axis) and comes to lie near the lighter 

 pole of the egg. Cleavage takes place in most 

 cases at right angles to the stratification. I 

 have been able to demonstrate that the cleav- 

 age planes stand in no relation to the original 

 egg axis. Nevertheless, the typical cleavage • 

 system generally appears. The primary axis 

 of the embryo, however, bears no fixed rela- 

 tion to the stratification. The fundamental' 

 question to settle therefore is what factor- 

 determines the location of the embryonic axis. . 



