2^2. MAINE AGRICUI^TURAIv EXPE;RIME;nT STATION. I912. 



Weight of Calves in Pounds. 





Age 



Normal 



Short-horn 



Males. (Meek) 



Triplet 



Short-horn 



Males. (Leathers) 



Six months 



■ 



Nine " 



351.5 

 505.6 

 698.3 . 



313.3 

 560.0 





740.0 







From these figures it is to be noted in the first place that 

 although the triplet calves were at six months of age some 38 

 pounds below the normal in weight, by the time they had 

 reached the age of nine months the mean weight per individual 

 of the triplets was not only equal to the normal weight for 

 Short-horn calves of the same age, but exceeded it by about 55 

 pounds. About this same degree of excess in weight was main- 

 tained during the next three months so that at one year of age 

 the mean weight per individual of the triplets was 42 pounds 

 above the normal as determined from Meek's data. It appears 

 then in the case of triplets, just as is known to obtain with twins, 

 that while the individuals start their free life at a lower weight 

 than is normal for single animals yet this defect is compensated 

 for in the subsequent growth. By the time the adult condition 

 is reached there is no difference in regard to size relations be- 

 tween the individuals which originate from multiple and those 

 which originate from single pregnancies. 



These facts seem to me to be of considerable interest in con- 

 nection with the dynamical hypothesis regarding growth recent- 

 ly published by Hatai."" It is to be presumed that in the case 

 of twins coming from two ova the original endowment of the 

 fertilized t.gg in respect to "potential growth energy" is the 

 same as in the case of a single offspring. Further, at the end 

 of the growth process both the twins and the single individual 

 attain the same bodily size (or volume). But the curve of 

 growth up to the time of birth must be considerably different 

 in the case of the twin individuals from what it is in the single 

 individual. During this period do the twins "grow at maximum 



^"Hatai, S. An Interpretation of Growth Curves from a Dynamical 

 Standpoint. Anat. Record, Vol. 5, pp. 373-382. 1911. 



