384 ANNUAL OF SCIENTIFIC DISCOVERY. 



tion of these red bands is to be assigned. If, says he, fruits wetted by dew 

 are observed whilst the rays of the rising sun strike upon them, it will bo 

 seen that the moisture collected in drops on the edge of the cavity in which 

 the stalk is inserted, and on the sides, forming lines of moisture, of greater 

 or less length, according to the size of the drops, and according as the sun 

 evaporates them with greater or less rapidity. It will be understood that 

 there must be great differences in the streaking, according as the dews are 

 more or less frequent, according as they arc light or heavy, and according to 

 the power of the sun's rays and the fineness of the skin. It is likewise prob- 

 able that the difference between the day and night temperatures has some 

 effect in this respect ; and streaked fruits arc generally autumn or winter 

 varieties. Pears arc seldom streaked, or, at least, not distinctly so. 



To throw some light upon the coloring of fruits, M. de Flotow has tried 

 the action of acids and alkalies upon the skin. The following are briefly 

 the principal results of his experiments : Strips of skin, removed from the 

 fruit and cleaned, became intensely red when treated with diluted sulphuric 

 acid ; at the same time they yielded a red juice. The color only became 

 brighter and more beautiful when treated with diluted hydrochloric acid. 

 Ammonia restored the original color. Other pieces of skin having been, in 

 the first place, treated with ammonia became brown, and their color dark- 

 ened to such a degree that they appeared black ; on the application of diluted 

 sulphuric acid their natural color was speedily restored. The Pommc douce 

 d' Amerique, which is streaked with bright red and pale yellow, underwent 

 no particular change when treated with sulphuric and hydrochloric acids, 

 the red lines only becoming a little more conspicuous ; and with ammonia 

 they became of a blackish-brown color. 



Whilst leaving to botanists and chemists the explanation of these facts 

 and several others contained in his memoir, M. de Flotow believes, however, 

 that he can conclude from them that the matter which reddens the skin of 

 fruits is totally different from the green matter which is also found there ; 

 and that it likewise extends to the flesh immediately under the skin 



VITALITY OF SEEDS 



The report of the standing committee of the British Association, on this 

 subject, was read at the Dublin meeting by Dr. Daubcny. 



They state that after planting, year after year, all the seeds they were able 

 to collect, they had now left, but four species of plants whose seeds continued 

 to grow. These were seeds belonging to the species Ulex, Dolichos, Malva, 

 and Ipomca. The results are curious and interesting. We now give them 

 for the information of our readers, and for reference. The register of every 

 experiment was exhibited with the details kept by Mr. Baxter of the Botanic 

 Garden. From this register it was seen that the shortest period for which 

 any of the seeds had retained their vitality was eight years, and the longest 

 forty-three years. Grouping the plants according to their natural orders, the 

 following, selected, will give some idea of the plants whose seeds retain 

 their vitality longest ; Graminese, eight years ; Liliaceae, ten years ; Coniferae, 



