108 REPORT OF THE CONFERENCE ON GENETICS. 
hybrids could be used as a criterion of the hybrid nature of intercrosses 
between the brown beans. 
The hybridisations were performed in the summer 1904 during a visit at 
Svalof. My friend Dr. Tedin, the excellent scientific assistant at Svalof, 
who is specially trained in the technical difficulties as to intercrossing the 
leguminous plants, has been so kind as to make all the intercrossings 
for me. I most heartily thank him for his great amiability on that 
occasion. 
The following hybridisations succeeded : 
MM x BB 
E xMM 
E x SE and SE xE. 
A germ produced by intercrossing is developed in a testa belonging to 
the mother-plant. The germ is “ fused”’ in the “ forms ” of the mother- 
plants, and here it was quite impossible to recognise in any case whether 
the hybridisation is realised or not. But when the seeds germinated the 
hybrids of EK x SE were easily recognisable by the purple colour-stripes on 
the stem—a character belonging to SK. The seeds of these guaranteed 
hybrids were characterised by dimensions (L, B, and J) the average values 
of which—each plant regarded separately—were intermediate between the 
dimensions of the two parent-lines, and the same was found as to the 
weight of the beans. These characters evidently blend in the hybrid 
first generation (I',) and are therefore well suited for our studies. It was 
now a very easy matter to find out the real hybrids of the brown lines, 
giving also for each plant intermediate values as to the weight and dimen- 
sions of seed. Oulyin one single case I have been in doubt, because the 
plant in question (of the cross MM x BB) had only two seeds—a number 
too small for estimating with any certainty. 
The question now to be elucidated is whether or not the hybrids have 
au increased variability as to the weight and dimensions of the beans. 
The ripe beans were weighed and measured in the same manner as 
indicated in my paper on “ pure lines.” Here we shall only regard the 
results as to the weight, the absolute length and breadth. The correla- 
tions between length and breadth are too complicated to be treated here ; 
but in reality the breadth indices of the hybrids are—as we shall see— 
intermediate between the indices of the relative pure lines. 
All hybrid beans have been weighed ; but in the crop of 1905 I have 
weighed some portions taken at random from the pure lines. The 
results are tabulated in Table I., in which the hybrids are placed between 
their parent lines. 
All indications relate to the crop of 1908. 
The heading letters in Table I. signify :— 
n the number of individuals. 
A the average weight in centigrammes. 
o the standard deviation in centigrammes. 
V the coefficient of variability (100 o : A). 
S the coefficient of*skewness (see p. 102). 
E the coefficient of excess (see p. 102). 
