416 



THE AMERICAN NATURALIST [Vol. XLV 



It is the purpose of the present review to discuss some of the 

 recent work which has been done along biometric lines with 

 agricultural materials and on problems relating to the science of 

 agriculture. The list of literature at the end or the review based 

 on it does not aim at completeness either in respect to the period 

 or the field covered. Rather it is the aim to indicate the general 

 trend of work in this field and to discuss its points of strength 

 and of weakness. 



At the outstart should he mentioned a number of papers 

 which have dealt with the general subject of statistical methods 

 as applied to agricultural material. The general purpose of 

 such papers has been, on the one hand, to call the attention of 

 agricultural workers to the existence of such methods and to the 

 desirability of their use, and, on the other hand, to give some 

 account of the nature of the methods themselves. Here are 

 to be noted the papers of Albrecht, Roemer (introductory por- 

 tion), Schoute, Quante, Rietz and Smith, and Zaleskiego. The 

 last three papers are especially worthy of attention. The paper 

 of Rietz and Smith gives an excellent elementary discussion of 

 correlation. It further furnishes a most hopeful sign of the 

 rapid development in research standards in agricultural work 

 in this country. Zaleskfego makes keen analytical use of fre- 

 quency polygons in his I. reeding work. lie calls special attention 

 to the prime importance of not lumping together non-homo- 

 geneous material. Rather he urges studying the frequency 

 polygon derived from the progeny of each ''pure line" by itself. 

 Then later these separate polygons may. if there is reason for it, 

 be summed together to make a "general population" polygon. 

 But to start with the latter and neglect the biological units (pure 

 lines) which go to make it up is wrong. This insistence on the 

 strict biological or gametic homogeneity of material to be studied 

 by statistical methods is worthy of all commendation. 



Quante discusses from a general standpoint some of the prob- 

 lems of variation in agricultural plants. lie considers that a 

 definite morphological difference is certainly present between 



timing our attention next to special investigations we may 



