CHAP. VII. TABLE 0. 259 



fertilised, forming the eighth self-fertilised generation, 

 and were likewise intercrossed one with another ; but 

 this cross between plants which had been subjected 

 to the same conditions and had been self-fertilised 

 during the seven previous generations, did not effect 

 the least good ; for the intercrossed grandchildren were 

 actually shorter than the self-fertilised grandchildren, 

 in the ratio of 100 to 107. We here see that the 

 mere act of crossing two distinct plants does not by 

 itself benefit the offspring. This case is almost the 

 converse of that in the last paragraph, in which the 

 offspring profited so greatly by a cross with a fresh 

 stock. A similar trial was made with the descendants 

 of Hero in the following generation, and with the same 

 result. But the trial cannot be fully trusted, owing 

 to the extremely unhealthy condition of the plants. 

 Subject to this same serious cause of doubt, even a 

 cross with a fresh stock did not benefit the great- 

 grandchildren of Hero ; and if this were really the case, 

 it is the greatest anomaly observed by me in all my 

 experiments. 



(2.) Mimulus luteus. During the three first genera- 

 tions the intercrossed plants taken together exceeded 

 in height the self-fertilised taken together, in the ratio 

 of 100 to 65, and in fertility in a still higher degree. 

 In the fourth generation a new variety, which grew 

 taller and had whiter and larger flowers than the old 

 varieties, began to prevail, especially amongst the self- 

 fertilised plants. This variety transmitted its characters 

 with remarkable fidelity, so that all the plants in the 

 later self-fertilised generations belonged to it. These 

 consequently exceeded the intercrossed plants consider- 

 ably -in height. Thus in the seventh generation the 

 intercrossed plants were to the self-fertilised in height 

 as 100 to 137. It is a more remarkable fact that the 



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