176 specimens. The whites were very weak, and all of them died without flowering. But they reappeared each year, and in 1897 I succeeded in getting them to blossom. After that they proved to be constant and true to seed. The same is true for the red-nerved ones and for the oblongas, which are very typical and easily cultivated species.
Since 1895 I have each year sown Oenothera Lamarckiana, always taking care that the seed was pure. Fertilization was always artificial, with their own pollen, and with the exclusion of all insects. Yearly I had a thousand or more seedlings and regularly found among them a number of mutations. The new forms with which I already was acquainted reappeared each time; with a single exception no others have been added. The percentage of mutants remained the same each year, of course with slight variations.
Repeatedly I saw new species originate which either did not flower or were sterile or which on account of general weakness succumbed early in life. Some of these clearly originated several times, others so rarely that it was practically impossible to make a diagnosis. A few of these I also found in the original locality. Hence nature evidently makes besides species capable of existence also those which are not so. The latter disappear very soon and hence are hardly ever seen; the former persist for a greater or smaller number of years.
The above may be considered sufficient to prove that the origin of species is a phenomenon falling entirely within the limits of ordinary observation. One has but to search his surroundings for a plant which happens to be passing through a mutation period to be able to study the entire process. Transportation to the garden only serves to make isolation of the plant possible; it but shows what happens in nature, but which there, on account of unfavorable conditions, is but seldom or imperfectly observed.
At the same time one sees that experiment, in this first example, confirms the deductions made a long time since from paleontological and biological data.
Delboeuf, as well as Scott, requires that each new species does not appear in a single specimen, but in a number of specimens, and not once but during a number of years. For only under these conditions are their chances sufficient. It is exactly this which happens with the Oenotheras. They are formed each year, 1 per 1,000 or 1 per 100, in any case in a sufficiently large number to fall within the requirements formulated by the savants just mentioned. They are with a single exception at once constant from seed, without ever returning to the type of the mother species; they would, by sufficient isolation, at once form groups of uniform individuals. Nothing indicates their appearance in advance, there is not even a hint of transition; once formed
