522 On the Distribution of the Means of Samples 
accordingly present features of interest quite apart from the particular case of 
the opsonic index. These remarks apply with special force to medical statistics 
which so frequently involve the use of ratios or indices. 
The importance of the problem tempted us to devote some little time to a 
theoretical consideration of the subject and we arrived at a few analytical results 
which might, we thought, be of some value. It is, however, unnecessary for 
us to publish these incomplete investigations, since Professor Karl Pearson has 
succeeded in obtaining a full solution of the problem*. We therefore confine 
ourselves to an empirical solution which is sufficient for our immediate object. 
140 
130 
120 
110 
Opsonic Index. 
Geaph 6. Curve of 25's secondary without replacement. 
* See the following paper. 
