472 
Intra-Class and Inter-Class Correlations 
a certain number of cases for the purpose of testing the form of the regression 
curve. 
Finally, in emphasizing the use of Intra-class and Inter-class Coefficients it 
may not be out of place to warn the reader that, as in the case of many other 
statistical relationships, the raw or uncorrected values may give quite erroneous 
impressions of the biological relationships under investigation. Some such cases 
will be discussed later. In the meantime, the purpose of this paper will have 
been fulfilled if the range of illustrations proves suggestive of wider application 
and if the formulae prove as useful to other biologists as they have to workers 
iu my laboratory, where they have been very extensively used and have become 
indispensable tools. 
In conclusion I take great pleasure in thanking most heartily the Editor of 
this Journal for the kindly criticisms and suggestions which have materially 
improved the manuscript. 
