20 GERMINATION OF THE SEED. CHAP. I. 



branching out into minuter divisions as they recede 

 from it. 



It passes But it remained to be proved by experiment that 

 the cotyle- the above are the vessels through which moisture 

 is conveyed to the plantlet. It was thought that 

 the fact might be ascertained by means of moisten- 

 ing the germinating seed with a coloured fluid, 

 which was accordingly done by Gleichen, Bonnet, 

 and Senebier, who found as tho result of their re- 

 spective experiments, that the fluid had tinged the 

 vessels of the lobes.* This was a presumptive 

 evidence of their use, but was not quite decisive; 

 for it was still possible that the fluid might have 

 entered by the radicle, and then passed into the 

 lobes. But when Bonnet moistened only part of 

 the cotyledons with a coloured fluid, he found the 

 plantkt tinged also. The fact seemed now satis- 

 factorily ascertained ; but other expedients were 

 also adopted with a view to prove or confirm it. 

 The cotyledons were cut off altogether, and the 

 plantlet thus committed to the soil. This experi- 

 ment had been made indeed by Malpighi at a much 

 earlier period, though not with the same view.-|~ 

 But the result was the same in both cases. The 

 plant perished under the experiment. It perished 

 even when the cotyledons were cut off after ger- 

 mination had made some progress ; or if it did not 

 absolutely perish it remained stunted and dwarfish. 



* Scneb. Fhys. Veg. vol. iii. p. 363. 

 t Anat, Plant. Pars altera, p. 18. 



