242 M. A. de Candolle on Germination 
I will first describe my experiments, and afterwards give the 
results. 
§ 1. Details of the Experiments. 
I first procured the seeds of ten species, in good condition, 
and belonging to several different families of plants. They were 
of or below the average size, some suitable for germinating at 
low temperatures, others requiring heat—at least according to the 
ordinary modes of culture. I selected three Cruciferee (Lepidium 
sativum, Sinapis alba, and Iberis amara), one of the Polemoniaceze 
(Collomia coccinea), one of the Linacez (Linum usitatissimum), one 
of the Cucurbitaceze (Cantaloup Melon), one of the Ranunculacee 
(Nigella sativa), one of the Sesameze (Sesamum orientale), one of the 
Leguminose (Z7rifolium repens), and one of the Graminaceze (Zea 
mais, var. precox). Notwithstanding the importance of the last 
two families, I preferred a single species only of each. The Legu- 
minose are well known for their irregular germination. It is 
not an uncommon circumstance, in the same sowing of the lupine 
or Vicia, to see the seeds sprout up week after week, month after 
month, and even until the following year, without our being 
~ able to account for it*. The Graminacee germinate somewhat 
slowly, and are furnished with an envelope (pericarp) adherent 
to the grains, which perhaps complicates the physiological 
phenomena. 
After having convinced mnyself that all my seeds were suscep- 
tible of germination, they were deposited in a dry place, where 
the temperature varied but little, and from which they were re- 
moved for each experiment. In each case they were sown upon 
sand in an earthen vessel, a wooden box, or a glass bottle, ac- 
cording to circumstances. The seeds were laid upon the dry 
sand, and each sowing, thus prepared, was left for twenty-four 
hours at least in the medium the mean temperature of which they 
were to acquire ; they were then watered with water of the tem- 
perature wished for in the experiment. The first watering was 
always copious, so that the seeds might be rapidly penetrated by 
the moisture—a necessary condition for their germination being 
induced by the temperature and the oxygen. The seeds were 
covered with a thin layer of sand, but the watering nearly always 
uncovered them. In fact, I have not remarked any difference in 
regard to the period of germination between the seeds upon the 
surface and those which remained covered by a thin layer of 
* T formerly pointed out to M. Vilmorin, senior, that Vicia narbonensis 
was a plant which would form excellent forage if its proper cultivation 
could be carried out. This skilful horticulturist took great trouble, and 
after having proved the real merits of the species, was compelled to 
renounce it, because he could not succeed in making the seeds gathered 
and sown together spring up at the same time. 
