50 SIPHONED. 



Additional evidence in favour of the influence exerted by 

 the horns consists in the fact of the capsules or seed-vessels 

 being either perforated or prolonged into a short tube, just at 

 the place where it comes in contact with the horn. This aperture 

 may fairly be presumed to be intended to facilitate the admission 

 to the spores of the granular matter discharged by the horns. 



Allusion has already been made in the Introduction to the 

 powers which many Conferva possess of resisting low degrees 

 of temperature. The spores of the different species of 

 Vaucheria would appear to be endowed with this power to a 

 remarkable extent. " In spite of all my precautions, the 

 frost of winter reached the water of my vase, and my grains 

 became enveloped (engage.es) in very thick ice. They remained 

 thus until the period of the thaw, that is to say, during 

 fifteen days, and when they reappeared, I believed them at 

 first to be too much injured to hope for any success ; but I 

 called to mind very opportunely the experiments of Spallan- 

 zani upon the different degrees of cold which seeds would 

 bear, without losing in consequence the faculty of germination ; 

 and well convinced that the Conferva exposed to the open 

 air had not been more fortunate than mine, I resolved not 

 to abandon my observations." The observations were con- 

 tinued ; and, as states the text, the grains germinated, to the 

 infinite delight of Vaucher, 



This faculty of resisting cold is bestowed upon the Vau- 

 cheria and many Conferva, and especially upon their seeds, 

 with the evident design of guarding against the extinction of 

 the species, which would be almost certain to occur upon the 

 freezing up of the waters of the ditches in which they are 

 usually found. The power also which these plants, and es- 

 pecially their seeds, retain of sustaining high degrees of tem- 

 perature, is scarcely less remarkable, and is doubtless im- 

 parted to them with a similar provident intention. This 

 power in the case of the spores is to be explained by reference 

 to the compact capsule which surrounds them, and which 

 prevents the evaporation of the interior moisture. Another 

 precaution adopted by nature to guard still further against 

 the risk of the extermination of any species, is the fact 

 that very many Conferva (the Vaucheria included), and 



