G. GASPAfrRtNt ON THE RIPENING OF FIGS. 



13 



scale, a hundred of these scales will represent altogether a surface 

 of 4 of a square inch, equal to the fifth part of the entire 

 superficies of the receptacle, which amounts to 3 square inches. 

 This "being premised, since the scales, like other organs, have the 

 power of attracting much sap, it would necessarily follow that 

 they would increase in size and would exhale abundantly, — two 

 functions which accompany each other wherever there is growth in 

 contact with the air, but which fail when we anoint the scales, al- 

 ready arrived at their perfect growth, and in which the exhalation 

 ceases entirely, or is very weak, the place which they occupy 

 being for the most part free from the influence of light and air. 



As regards the sulphuric acid, this observation must be made, — 

 that, as it has a great affinity for water, it would attract the sap to 

 the body of the fig at the end of the branch. But so many other 

 acids and fatty matters do the same without possessing the 

 faculty of attracting water. Besides, the sulphuric acid, after the 

 manner and under the conditions before stated, by altering the tis- 

 sue of the scales, kills them, while it excites on the other hand the 

 vegetation of the entire receptacle more strongly than any other 

 substance which has been tried hitherto, promoting the increase 

 and maturation in less time. The exciting-power of this acid 

 on certain vegetables, especially lucern, has been known for many 

 years, whether used alone, diluted with water in the ratio of one 

 to a thousand, or combined with lime. But I wish to give another 

 illustration of its bearing on the present subject. At the end of 

 the year 1815, when treating of caprification, I noted that the pollen 

 of the Wild Fig, kept in water, seldom or never protruded the 

 pollen-tube, and that this took place easily by slightly acidulating 

 the water with azotic acid. In the present year I have confirmed 

 this observation, and obtained in like manner the pollen-tube in 

 a few hours in water scarcely acidulated with sulphuric acid, 

 V whale from the pollen kept in common water not a single pollen- 



tube was protruded in the course of three days. 



It appearing, on the other hand, that the scales at the mouth 

 of the fig are sensitive to the action of sulphuric acid and 

 the other substances above mentioned, it remains to ascertain 

 what relation this sensibility inherent in the scales bears to 

 similar functions in other plants. But we must first shortly call 

 to mind the origin, formation, and structure of the fruit of the 

 fig, known to science at various times under the name of" sicono," 

 "anfanto,"and more generally under that of "receptacle." It springs 



