GROWTH AND SENESCENCE 



5i 



growth. This formula, too, is one used to represent the course 

 of change of certain chemical reactions, which is in harmony 

 with our tentative generalization or law that the course of 

 growth may be limited by a physico-chemical reaction. 



(b) Growth in weight. — While the formula (2) can be used 

 to represent nearly the whole of the extra-uterine period of 

 linear growth in cattle, it can be used to represent growth in 



Ag<? 



Figure 33. Growth in weight of the dairy cow. The circles 

 are observed values, the smooth curve was drawn from 

 the equation given on the chart. The agreement between 

 circles and curve is excellent after the point of inflection, 

 which is about five months after birth. 



weight in this species only following the age of about five 

 months after birth. Figure 33 illustrates this statement. The 

 circles represent observed values; the smooth curve was plotted 

 according to the equation shown in the chart. Satisfactory agree- 

 ment between observed and computed values does not begin 

 until about fifteen months after conception (i.e., three to six 

 months after birth). When the theoretical curve is extrapolated 

 it meets the age axis not at zero, but at 8.9 months. 



What was said respecting the agreement between observed 

 and computed values for the cow is also true for all other ani- 



