POPULAR MIS CELL ANY 



855 



labor through a whole season with nothing 

 more than this, he is liable to develop a sub- 

 acute bronchitis, and occasionally a more 

 dangerous affection. The morbific effects 

 increase in the second and third years, and 

 the shoveler will at last probably have to 

 go to the hospital with a peculiar pulmo- 

 nary disease, which may be of every grade 

 and usually affects both lungs. The attack 

 fixes him in the ward for at least three 

 months, after which he may wholly recover 

 if he goes into a new business, but, if he 

 returns to his shoveling, he will soon fall 

 a victim to lung-disease. A very few men 

 continue to work in the elevators till they 

 become old ; and it appears that those who 

 begin it at thirty-five or forty years of age 

 bear it better than those who begin at 

 twenty. Dr. Rochester considers a regula- 

 tion and limitation of the hours of continu- 

 ous labor, the sanitary regulation of lodging 

 and boarding houses, and restriction in the 

 use of ardent spirits, essential parts of any 

 measures for checking this disease. 



Th Green Color of Oysters. The fact 

 that the green color of some oysters is 

 caused by a variety of navicula, which is 

 called Navicula ostrearia, is illustrated and 

 established by experiments which have been 

 recently made by M. Puysegur, at Sissable. 

 A quantity of the green slime scraped from 

 the edges of the ."clears" was put, after 

 the mud had been allowed to settle, into 

 soup-plates. Perfectly white oysters, which 

 had never been in the "clears," and the 

 shells of which had previously been washed 

 and brushed clean, were then put into the 

 fluid. Other precisely similar oysters were 

 put into plates of ordinary sea-water. In 

 twenty-six hours after the beginning of the 

 experiment, the oysters charged with dia- 

 toms had all acquired a marked greenish 

 hue, while the other oysters remained un- 

 altered. The experiment was repeated sev- 

 eral times, with identical results ; and the 

 green color in the oysters was found to be 

 more decided in proportion as the water was 

 more highly charged with diatoms. The 

 greenness disappeared on leaving the oyster 

 for a few days in ordinary sea-water, to ap- 

 pear again when it was put in fresh water 

 containing the navicula. It appears that 

 the diatoms are drawn into the stomach of 



the oyster with the currents wliich it in- 

 duces, and there part with their nutritive 

 constituents. The chlorophyl is digested, 

 and imparts its color to the blood, whence it 

 happens that the most vesicular parts of the 

 structure, as the bronchiic, are most highly 

 colored. The fact of the absorption of the 

 diatoms was proved by the examination of 

 the digestive tubes of the oysters experi- 

 mented upon. Their stomachs, intestines, 

 and exuviae were strewed with carapaces of 

 naviculae. 



Dcep-Sea Explorations off the Coast of 

 France. A commission appointed by the 

 Minister of Public Instruction in France 

 has just accomplished an exploration of the 

 depths of the Gulf of Gascony, and of a 

 great submarine valley which lies parallel 

 to the coast of Spain. The commission was 

 composed of MM. Milne -Edwards, father 

 and son, and several other naturalists, and 

 Mr. Gwyn-Jeffreys and the Rev. Mr. Nor- 

 man, of England. The expedition was com- 

 pletely successful, having collected at least 

 five hundred species, nearly all of which are 

 new to the fauna of the Gulf of Gascony, 

 and some of which are new to science. Pre- 

 vious to this expedition, Messrs. Gwyn-Jef- 

 freys and Xorman had explored the fosse, 

 or ditch, of Cape Breton, a curious sub- 

 marine cavity in the sea-bottom of the de- 

 partment of the Landes, in which a connec- 

 tion was traced between the fauna of the 

 Mediterranean Sea and of that part of the 

 Gulf of Gascony. 



M. Delannay's Theory of Earthqnakes. 



M. J. Dclaunay has proposed a theory 

 that earthquakes, as well as many meteoro- 

 logical phenomena, are produced by the 

 passage of the planets through the masses 

 of meteors. The more severe seismic tem- 

 pests, he believes, are caused by the passage 

 of the larger planets through the cosmic 

 groups, particularly through those in longi- 

 tudes 135' and 265, which appear to give 

 rise to the August and November meteors. 

 The passages of Venus, the Earth, and Mars 

 through the groups seem to occasion only 

 earthquakes of a secondary order ; but each 

 6f these planets produces on its passage an 

 increase of shocks in the months of August 

 and November. The most violent and long- 



