GROWTH OF THE SKELETON 313 



EFFECT OF THE INFLUENCE OF THE MACERATING FLUID ON THE 



USE OF THE DATA 



In the first place, it is evident that if we desire to obtain the 

 true weight of the skeleton or any of its parts — using the values 

 for the dissected bones as standards — it will be necessary to 

 correct the observed values of the macerated bones in accordance 

 with the percentages of loss given in table 34. 



When, however, it is a question of the relative weights of the 

 various parts of the skeleton among themselves, then we may 

 safely assume that the effects of the macerating fluid are so similar 

 on the several parts, that the relations found would be substan- 

 tially those existing among the fresh bones. 



Finally, if it is desired to compare the parts of the skeleton in 

 any rat which has been subjected to conditions that might 

 modify the weight or condition of the skeleton during life, then 

 the observed values given in our tables may be used as a basis 

 for this comparison, provided the skeleton of the test rat has 

 been prepared by the same or a similar process of maceration. 



It appears therefore that, despite the very considerable modi- 

 fications induced by the use of the macerating fluid in the 

 weights and water content of the bones, the observed and uncor- 

 rected values are nevertheless trustworthy for showing the rela- 

 tions between the parts, and may be used also as standards for 

 comparison with other skeletons prepared in a like manner. 



All the results in this paper are subject to at least the fore- 

 going corrections, but such corrections have not been made. 

 The values given in the tables are based on those which were 

 observed. 



WEIGHING AND MEASURING 



The various groups of bones were weighed immediately after 

 cleaning (giving the 'fresh weight'), they were then dried for 

 thirty days or more at room temperature, and again weighed 

 (giving the 'room-dried weight'), and finally were dried at 96°C. 

 for six days and weighed (giving the 'oven-dried weight'). 



Measurements of the length of the long bones were also made 

 with a dial calipers reading to 0.1 mm., in the three different 

 conditions of moisture. 



