and Functions of Bulbs in general. 457 



not contributed to the nourishment of the plant ; since the roots 

 with which it was furnished were quite sufficient, by the nourish- 

 ment they extracted from the soil, to restore the substance that 

 might have been expended. I kept this bulb out of the soil for 

 some time; and found that the roots soon dried up, but that the 

 leaves continued to vegetate till the white part of the bulb had 

 become reduced to a little withered point. Thus I obtained 

 another fact in support of my opinion. 



The manner in which the bulb decays, according to the ordi- 

 nary course of vegetation, cannot be better explained than 

 by admitting this particular mode of nutrition. As soon as the 

 bundles, already spoken of, are completely developed, they 

 begin to afford nourishment to the offsets. The leaves of these 

 bundles, which before elaborated the sap sent up to them by the 

 roots, to supply nourishing matter to restore the substance lost 

 by the parent bulb, now, having formed witli their bases the 

 innermost coats of the offsets, deposit the nourishment they 

 contain to augment the bulk of the latter. 



The substance of the bulb continues to be absorbed and cir- 

 culated ; passing to the leaves from the germ, probably by the 

 filaments {e inj%-. 73.) which issue from each of its tubercles; 

 and, as we have already seen, the substance being no longer 

 reproduced, the parent bulb necessarily decreases in bulk, till, 

 by little and little, it disappears. What merits particular atten- 

 tion here is, that the leaves become yellow as the substance 

 of the old bulb diminishes, and, like it, perish. 



It has been observed, that plants having solid bulbs contain 

 in all their parts a great deal of mucilage, into which it is well 

 known that starchy substances are easily converted ; and this 

 observation, combined with the delicate texture of the plants (a 

 texture analogous to that of young plants or leaves, which 

 have had no other nourishment than the starchy substance con- 

 tained in the cotyledons or alburnum from which they spring), 

 serves still further to corroborate my opinion. Solid bulbs are, 

 then, according to my hypothesis, masses of starchy matter, 

 provided by nature to serve as a support to the young plant, in the 

 same manner as the albumen of the Qg^ serves to nourish the 

 chicken. 



Whether scaly bulbs and tubers are destined by nature to 

 perform the same office, I have not yet had sufficient experience 

 to determine: but, as they contain a mucilaginous, or starchy, 

 substance ; and as the parts that proceed from them abound in a 

 similar kind of mucilaginous matter, and have all the delicacy 

 of texture mentioned ; and as I have observed that the onion, 

 while kept out of the ground, germinates, and continues to grow 

 till it has reduced the bulb to a congeries of withered coats ; that 

 the iScilla, in a similar situation, will even flower ; and that the 



