Since the rolled leaves are at the same time board and lodging, we have but to pick them, from the vine and the poplar respectively, and to place them in the glass jars, whence we can take them at such times as we consider suitable. What used to be [[132]]effected in the open air, amid the disturbances of the atmosphere, will be effected all the better in the peaceful shelter of the glass. There can be no doubt, therefore, of an easy success.
But what is this? From time to time I unroll a few cigars to ascertain the state of their contents. What I see fills me with anxiety for the fate of my baby-farm. The young larvæ are very far from thriving. I find some of them languishing and emaciated, shrivelling into a wrinkled ball; I find some of them dead. Vainly I possess myself in patience: the weeks go by and not one of my grubs grows or gives a sign of energy. From day to day my two colonies dwindle until they consist wholly of dying larvæ. When July comes, there is not a living thing left in my glass jars.
All have died. And of what? Of starvation, yes, of starvation in a well-stored granary. This is evident from the small amount of food consumed. The cylinders are almost untouched; at most I perceive in the midst of their layers a few scratches, the traces of a scornful tooth. Probably the food was too dry, had been rendered uneatable by desiccation.
Under natural conditions, while the burning heat of the sun hardened the leaves by day, the mists and the dew softened them at night. Thus, in the heart of the spiral layers, a column of soft crumb is preserved, a necessity for the tender nurselings. A sojourn in the uniformly dry atmosphere [[133]]of the jars has, on the other hand, turned the roll into a hard, stale crust which the grubs refused to touch. The failure is due to that.
A year later, I begin again, this time more cautiously. The rolled leaves, I said to myself, remain hanging for some days on the vine or the poplar. The perforation of the leaf-stalk has not completely severed the ducts conveying the sap; a scanty flow still persists and for some time maintains a certain flexibility in the leaf, especially in the centre of the spiral, which is not exposed to the action of the sun. Consequently the new-born grub has fresh provisions within reach of its mandibles. It waxes big and strong and acquires a stomach able to satisfy itself with less tender food.
Meantime, from day to day, the roll turns brown and dry. If it remained indefinitely hanging on the bough and if, as often happens, there were a lack of moisture at nights, it would dry up completely and its inmates would perish as they did in my glass jars. But, sooner or later, the wind shakes them off and they drop to the ground.
Their fall is the salvation of the grub, which is still very far from full-grown. At the foot of the poplar, under the grass of the meadow subject to frequent irrigation, the soil is always damp; at the foot of the vine-stock, the earth, overshadowed by the branches, fairly well retains the moisture of the last showers. Lying in the wet and sheltered [[134]]from the direct onslaughts of the sun, the Rhynchites’ victuals remain as soft as need be.
Thus I argued, meditating a fresh experiment; and the facts confirmed the accuracy of my forecast. This time all goes well. Rather than the green rolls of recent manufacture, I gather the brown cigars which are due to fall to the ground. The larvæ in these latter, being older, are less difficult to rear. Lastly, my harvest is installed in glass jars as before, but on a bed of moist sand. With this and this alone I achieve complete success.
Despite the mildew which this time invades the heaped cigars and seems bound to jeopardize everything, the larvæ thrive and grow without hindrance. The decay which I distrusted so much in the beginning, when I kept my crops dry to avoid it, this decay suits them. I see them taking big mouthfuls of decomposing shreds, the tainted remains of leaves that have almost turned to mould.
I am no longer surprised that in my first experiments my nurselings allowed themselves to die of hunger. Obeying a mistaken idea of hygiene, I took pains to keep the rations in good condition, in an atmosphere free from mustiness. I ought, on the contrary, to have allowed fermentation to do its work, softening the tough tissues and enhancing their flavour.