fibrous structure, and forms the central and lower 
part of the little bulb, or base of the flower- 
sheath, which forms above the large bulb. From 
the structure of this part, its position, and the 
circumferential and fusiform roots (which will 
be described presently) proceeding from it, I con- 
sider it as the vital speck or germ of the little 
bundle or sheath which springs from its upper 
part. The other portion which remains to be 
described has the appearance of the old bulb, 
being of a milk-white colour, and of a homo- 
geneous texture, except some threads or filaments 
in one part, which are more or less apparent, 
and which cross it vertically, proceeding from 
each of the tubercles before-mentioned. It has 
| been observed that, as soon as the vegetation 
commences, the offsets of the bulb send down 
from their base or side one or more large fusiform 
roots, which have their origin in the internal 
part or germ of the solid substance above de- 
scribed. Whether these are intended to assist 
the circumferential fibrous roots in the office of 
absorption, need not be discussed here, as it is 
apparent that these latter cannot absorb suffi- 
cient matter for the formation of the offsets; 
and this is proved more fully by observing that 
there are sometimes no fusiform roots when only 
one offset is developed, the circumferential roots 
in that case appearing to be sufficient for its 
nourishment. As vegetation proceeds, the off- 
sets are found to augment in bulk; but when 
observed internally, their germs are found not 
to have increased at all, and that only the parts 
which surround them are enlarged; so that, 
when the bulb is completely developed, the germ 
has vanished, leaving only a faint trace of shade, 
showing where it has been, and which may be 
observed in the lower part of the. bulb. In pro- 
portion as the offsets become larger, the parent 
bulb diminishes, becomes yellow and dried up, 
| presenting only a fibrous cellular structure ; 
which, when the new bulb has attained its ut- 
most growth, becomes black, and dwindles away 
to a very small substance that, sooner or later, 
disappears altogether. The circumferential 
roots decay with the bulb, and the fusiform 
roots also; the leaves become yellow, wither, 
and finally rot off; and their bases, which 
have become the inner coats of the dried bulb, 
with their internal sheaths, remain on the in- 
volucrum of the offset. The bulb thus passes 
on into its dormant state. The newly formed 
bulbs, which at first participated in the vital- 
ity of the old ones, (by means of the prolonga- 
tion of their germs, which united nearly in 
the centre of the old bulb, and were the origin 
of the circumferential roots,) now enjoy an in- 
dividual vitality ; they have no longer any germ, 
as that by degrees has withered, and finally dis- 
appeared ; and these bulbs, in their turn, can 
now only be considered as a mass of matter con- 
taining the germs of the new plants, which are 
to be developed at the next season of vegetation.” 
BULB. 575 
The bulb of Gladiolus communis, the bulb of 
Colchicum autumnale, and even the bulb or tuber 
of Corydalis bulbosa or Fumaria bulbosa solida, 
were observed by Dr. Trinchinetti to vegetate 
very similarly to the bulb of Crocus sativus; ex- 
cept that the offsets of the second of these always 
appear at the side of the parent bulb, and, hav- 
ing a free base, produce immediate capillary roots, 
which probably perform the same office as the | 
fusiform roots of the crocus. 
Dry solid bulbs, such as those of crocus, if placed 
on a board or in any other situation, where they 
cannot form roots or obtain nourishment from 
the soil or from water, will sprout with great 
vigour, and, in some instances, will even grow 
so long and so healthfully as to produce flowers ; 
but they gradually become lighter,—they even- 
tually shrink and shrivel,—and, when they have 
expended all or nearly all the starchy matter of 
which their interior substance was composed, both 
they and their shoots irretrievably perish. When 
bulbs of the same class grow in the soil or in water, 
they simply replenish through their roots the 
succcessive portions of their interior starchy mat- 
ter which are consumed in feeding their shoots ; 
and all such bulbs, therefore, additional to their 
functions of forming germs, defending embryos, 
and producing offsets, may be regarded as stor- 
ages of food for the nourishment and mainte- 
nance of their respective species of plants, up to a 
point when reproduction is effected or new in- 
dividuals brought into existence by the matured 
formation of offsets. “ Whether scaly bulbs and 
tubers,” says Dr. Trinchinetti, “are destined by 
nature to perform the same office as solid bulbs, 
I have not yet had sufficient experience to de- 
termine. But as they contain a mucilaginous or 
starchy substance, and as the parts that proceed 
from them abound in a similar kind of mucila- 
ginous matter, and have all the delicacy of tex- 
ture 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 
scilla, in a similar situation, will even flower, and 
that the tubers of the potato put out shoots and 
nourish them for some time, I think it may be 
admitted, that not only solid bulbs, but also 
those that are scaly and tuberous, are intended 
to nourish the plant with their substance.” A 
twofold inference of great practical moment to 
agriculture, from this concluding, and, as we 
think, sound doctrine of Dr. Trinchinetti, is that 
potato tubers intended for sets ought not to be 
ripened beyond the mere organic formation of their 
germs, and that, toward the close of winter and 
spring, they ought not to be allowed to sprout 
before being planted, or, in other words, before 
being placed in a situation to form roots for the 
replenishment of the starchy matter consumed in 
the formation of their shoots. How generally have 
farmers and gardeners observed that, at the time 
of digging the most productive potato plants, 
