DEPARTMENT OF EXPERIMENTAL EVOLUTION. 133 



The sheep experiment at the New Hampshire Experiment Station 

 has been continued. A strain of Hampshiredown-Rambouillet hybrids 

 has been nearly perfected, and shows in a high degree a union of 

 especially valuable qualities of fine wool and good conformation. In 

 addition the second hybrid generation of Southdown-Rambouillet 

 origin is being produced. 



With poultry we are continuing the prolonged selection for ''new 

 buff," studying the factors present in " bare neck," analyzing the genetic 

 constitution of certain new rumpless strains and of syndactylism. 

 There were 184 chicks hatched during the year. 



OTHER INVESTIGATIONS. 



CORRELATION BETWEEN CHARACTERS OF LEAVES IN NORMAL AND ABNORMAL 



BEAN SEEDLINGS. 



Dr. J. A. Harris has been breeding a strain of beans that produces 

 more than the two primordial leaves that constitute the normal 

 number. His problem was, How do the abnormal and the normal 

 plants compare in respect to total weight of leaves and sap density? 

 The results are as follows: When the cotyledons are of the normal 

 number, 2, but not attached at the same level, the total weight of 

 the leaf laminse is about 81 per cent of that of strictly normal plants. 

 In a sample of 100 seedlings, selected for greatest separation on the 

 stem of the cotyledons, the ratio is 79 per cent. Where there are 3 

 instead of 2 cotyledons and 2 primordial leaves the leaf-tissue is about 

 78 per cent of normal. Even when with 3 cotyledons there are 3 

 primordial leaves in place of 2, the total weight of their laminse is 10 

 per cent less than that of the normals. In fasciated plants about 25 

 per cent less leaf -tissue is produced than in normals. As for the cell- 

 sap, there is not a marked difference in concentration between normals 

 and abnormals. 



CORRELATION BETWEEN HOMOLOGOUS PARTS OF A PLANT. 



In plants there is obviously hereditary resemblance between the parts 

 of one and the same plant. Dr. Harris has determined for the legume 

 Cercis canadensis the correlations between the number of ovules to the 

 pod, number of seeds to the pod, number of abortive ovules, etc., from 

 different pods of one plant, and has compared his results with figures 

 obtained by other statisticians. The correlation of ovules is higher 

 in Cercis than in most other species studied; but the correlation in 

 number of seeds is about the same as obtained in other cases. 



VEGETABLE SAPS. 



Gortner, Lawrence, and Harris show ("The extraction of sap from 

 plant tissues by pressure," Biochem. Bull. No. 5, 139-142) that Dixon 

 and Atkins are indeed right in their caution that a sample of sap 



