52 Latent and Semi-Latent Characters. 



much as the plant is most sensitive in its early stages. 

 In this fonn of the experiment we can, so to speak, only 

 investigate the last vestiges of its former susceptibility. 

 Far more striking results are to be expected from experi- 

 ments with seedlings; but here a great uniformity in the 

 samples of the seeds is necessary for the results to be 

 reliable. It is not sufficient to mix the seed, but it is 

 advisable to harvest seed from two or three or still better 

 from a single seed-parent of known and pure ancestry. 

 It is even better to allow the influences that are to be 

 investigated to operate during the development of the 

 seed on the parent plant. 



In accordance with these considerations, therefore, 

 I cut one of my plants into two parts, one of wdiich I 

 transplanted into poor sandy soil but the other into 

 good garden soil, and allowed them to set seed. I was 

 thus able to study both the direct effect on the plant and 

 also the indirect effects on the succeeding generation. 

 (See Vol. I, Part III, pp. 521-522.) 



The experiment, which was carried out during the 

 years 1892-1894, was made with a single individual which 

 arose from the stock plant for 1891, mentioned on page 

 38 and marked S. This plant had, wdien it germinated 

 in 1892, a bimerous primordial leaf, and in the same 

 year bore seeds which, when sown in the spring of 1893, 

 gave rise to about 40% seedlings with a tetramerous 

 leaf. As soon as this was visible in the seedpan the 

 choice was made and the parent plant, which I had kept 

 through the winter in a bed, was cut in two and trans- 

 planted into the above mentioned kinds of soil. Both 

 halves grew well, although not with equal luxuriance ; 

 they flowered in July, were pollinated from the various 

 plants around them composing the main culture of that 



