i3° 



TEE POPULAR SCIENCE MONTHLY 



continuously at the rate of one, three and five seeds per hill 5 for six 

 years, he finds the yields given in the accompanying diagram, 1. 

 Apparently the seed grown under competition yields higher than that 

 grown under thin planting. 6 



GROWN FIVE PLANTS PER HILL 



GROWN THREE PLANTS PER HILL- 



©- 



GROWN ONE PL ANT PER HILL 



I 3 S 



Diagram 1. Yield of Maize from Various Types of Seed. 



The Selective Death Rate in Man. — Beyond all doubt the most 

 important work on the question of the existence of a selective death 

 rate has been done on man. This is true not merely from the stand- 

 point of the critical nature of the investigations and the soundness of 

 the conclusions, but from the sociological importance of the findings 

 as well. 



The pioneer work of Pearson and Beeton 7 already mentioned in 

 these pages has recently been supplemented by the studies of Ploetz. 8 

 However conclusive these studies may be, it is most important to have 

 light on this question from another angle. Precisely the information 

 needed should be obtainable in the following manner. 



If natural selection be a reality, then (other factors being rendered 



8 When planted at the rate of one per hill about 25 good ears weighing 

 12 ounces or more are produced to every 100 plants. With 3 plants per hill there 

 are only about 10 good ears, with 5 plants, only about five. A plant capable of 

 producing a good ear with four others in the same hill must be unusually vigor- 

 ous, but in thin planting it is not possible to tell which of the plants would have 

 been capable of reaching the high standard under keen competition. 



• The details given in Montgomery 's paper are entirely too meager for a 

 problem of such great complexity. 



t Pop. Sci. Mo., 78: 533-534, 1911. 



•A. Ploetz, "Lebensdaur der Eltern und Kindersterblichkeit. Ein Beitrag 

 zum Studien der Konstitutionsvererbung und der naturlichen Auslese unter den 

 Menschen," Arch. Bass.- u. Gesellschaftsbiol., 6: 33-43, 1909. 



