INHERITANCE IN ABNORMALITIES 443 



experiment. In the first experiment both members in 19 pairs 

 were affected; in the second experiment, both members in 8 

 pairs. Applying the formula (first experiment, n = 72, m = 228; 

 second experiment, n = 27, m = 194) we find that if pairing has 

 no effect on the matter, the most probable number of cases for 

 both members in the first experiment is 11; in the second, 2. 

 Similarly there are in the first experiment 61 pairs in which both 

 members divided, while the most probable number is 53. In 

 the second experiment the actual number is 79, the most prob- 

 able is 72. Again we find that conjugation increases the resem- 

 blance of members of pairs in this respect. 



It will be of interest also to give the relation of pairing to the 

 date on which the lines finally died out. This is known for both 

 members of but 51 pairs of the first experiment, and 41 of the 

 second. The numbers in the third experiment are too small to 

 be considered. In some cases the descendants of both members 

 of a pair completely died out on the same date; in other cases the 

 descendants of one member lived longer than those of the other. 



The main facts are these. In the first experiment, on Decem- 

 ber 5, twenty lines were found to have died out; these included 

 both members of 8 pairs. The probable number of pairs if con- 

 jugation does not affect the date of death is but 2. On Decem- 

 ber 7, 53 individual lines ended, including both members of 

 20 pairs. The most probable number of pairs would be but 14. 

 On later dates the numbers are too small to be significant. In 

 the second experiment on December 6, 31 lines were found to 

 have died out; these included both members in 7 pairs. The 

 probable number of pairs if pairing does not affect the date of 

 death is but 6. On all the other dates the numbers were so small 

 that they are not worth considering. Conjugation thus tends 

 to make descendants of the two members of a pair alike in their 

 length of life (in their 'vitality')- 



All together, the evidence shows that conjugation induces 

 resemblances in the two members of a pair in respect to all the 

 characters examined : in the tendency to fail to reproduce after 

 conjugation; in the abnormalities produced by their offspring; 

 and in the length of life of the stocks produced. 



