TO THE THEORY OF EVOLUTION. 
45 
Here I find r — ‘4708 + ’0292. 
A further table is of interest 
Laryngeal cases. 
Requiring 
tracheotomy. 
Not 
requiring it. 
| 
Totals. 
Without antitoxin, 1894 . . . 
261 
205 
466 
With antitoxin, 1896 .... 
188 
274 
462 
Totals. 
449 
479 
928 
In this case we have r = ‘2385 fir '0335. 
Lastly, I have drawn up a third table :— 
Total Infantile Cases, Ages 0—5 years. 
Recovery. 
Death. 
Totals. 
With antitoxin, 1896 . . . 
912 
434 
1346 
Without antitoxin, 1894 . 
615 
556 
1171 
Totals. 
1527 
990 
2517 
Here we have # r = '2451 fir '0205. 
The three coefficients are all sensible as compared with their probable errors, and 
that between the administration of antitoxin and recovery in laryngeal cases is 
substantial. But the relationship is by no means so great as in the case of vaccina¬ 
tion, and if its magnitude justifies the use of antitoxin, even when balanced against 
other ills which may follow in its train, it does not justify the sweeping statements of 
its effectiveness which I have heard made by medical friends. It seems until wider 
statistics are forthcoming a case for cautiously feeling the way forward rather than for 
hasty generalisations. 
Illustration VIII. Effect on Produce of Superior Stock .—To find the effect of 
superiority of stock on percentage goodness of produce. 
To illustrate this and also the formula (lxxxiii.) for six correlation coefficients, we will 
investigate the effect of selecting sire, dam, and one grandsire on the produce when there 
* The values of r for all the three cases of this Illustration were determined with great ease from 
Equation (xxiv.). 
