92 SHINKISHI HATAI 



In making these weighings I had the help of Miss Wolfe and 

 Miss Conrow and desire to acknowledge here my indebtedness 

 to both of them for their accurate work. 



The formulas and their application 



By means of a mathematical formula the relations between the 

 weight of the body and that of the organ have been expressed in 

 each case. Such formulas have an evident use for the purpose of 

 interpolation, while for the study of various growth phenomena, 

 such as relative rate of growth, form of graph during various 

 stages of life, and so forth, they give a proper basis for discussion. 



In expressing the weight relations mentioned above, I have em- 

 ployedatypeof formula (Hatai'll) which may bewritten as follows: 



Y = aX + 6 log X + c 



or in some cases a simpler form was used 



F = 6 log X + c 



where Y = weight of organ; X = body weight; a, h, c = con- 

 stants; to be detennined from the observed data. 



In the case of the sex glands it was necessary to use the two 

 formulas in order to express the several phases of growth, that is 



Y ^ a + hX H- cX- for one phase and 



Y = h log X + c for the other phase. 



In detemiining the constants of the formulas, I have used as 

 far as possible the data obtained from the rats reared in The 

 Wistar Institute. This procedure was important in order to 

 avoid the mixture of data. 



In some instances however, I have made use of the data ob- 

 tained by Dr. Jackson, when my own observations were too few for 

 an adequate treatment. Dr. Jackson's data were used, as follows : 

 ^ 1. For studying the eyeballs and ovaries I have used only the 

 data obtained by Dr. Jackson. None of my own observations 

 were employed. 



2. For studying the suprarenals, thyroid and alimentary tract, 

 I have used the data obtained by Dr. Jackson to fill the interval 



