414 



JAAIES STUART PLANT 



TABLE 2 

 Percentages of gain of averaged entries of table 1 



PAIRS AVERAGED 



First three entries. 

 Last three entries. 



days 



55 

 150 



INITIAL WEIGHT 



1 



grams 



1.612 

 1.803 



grams 



1.539 

 1.689 



.A.VERAGE PERCENTAGES OF GAIN IN 

 MGLLERS FLUID 



24 



hours 



20.1 

 27.0 



7 

 days 



30.5 

 37.0 



14 

 days 



26.8 

 35.0 



30 

 days 



25.4 

 32.1 



75 

 days 



24.7 

 31.2 



tion. If we make a comparison of the individual brains of the 

 respective pairs involved in table 1, however, we maj^ study the 

 effect of initial brain weight in animals of like age. The data 

 are given in table 3. In place of the percentage of gain of the 

 lighter brain there is entered at the several columns marked 

 'Per cent deviation of 2' — under 'Time in Miiller's fluid' — only 

 the relation of that percentage to the percentage of gain of the 

 heavier brain. Of the fifteen pairs involved, it will be noted 

 that in twelve the lighter brain gains more in the first twenty- 

 four hours (represented by a + in the second column). Also in 

 twelve of the fifteen pairs, the heavier brain later 'catches up' 

 — that is, the relative gain of the heavier brain is greater at 

 seventy-five days than at one day. This phenomxcnon is clearly 

 demonstrated in the 'averages' at the bottom of the table. The 

 results may be summarized as follows: 



Thus it appears that the lighter brain gains more in the early 

 part of the stay in Miiller's fluid, but that this difference prac- 

 tically disappears at the seventy-five-day weighing. It is to be 

 noted that the standard deviations are lowest at the seven-day 

 weighing. This seems to represent the period of least indi- 

 vidual variation. As this represents the time of maximum 

 increase, we may consider that as the more stable period in the 



