556 
said to be linebred the results of each 
mating must be bred to animals closely 
related to the original sire or dam. One 
can readily see that animals can be 
closely inbred from generation to gen- 
eration and still be carrying less and 
less of the blood of a certain ancestor, 
while by linebreeding the proportion 
of that blood can be constantly in- 
creased. 
Felch’s well-known chart of line- 
breeding is often misunderstood. Many 
see only the great number of combina- 
tions possible from one mating. The 
chart shows more than that: it shows 
how the blood of a certain pair of ani- 
mals can be amalgamated. This is 
seen by following the central lines. 
But it also shows that by following a 
one-sided system the blood of either 
sire or dam can be increased and the 
tendency to transmit certain charac- 
teristics intensified. Breeding a colt 
back to his dam is inbreeding. It is 
The Journal of Heredity 
also linebreeding with reference to the 
dam, but it is not linebreeding with 
reference to the sire. Now it would be 
easy to find plenty of animals related 
to the new colt and yet unrelated to 
the sire, and it is a gross error in such a 
case to say that linebreeding is the same 
as inbreeding. It is to be hoped that 
writers will continue to give these terms 
their true meaning, which will be done 
by using them as they were used by 
those who first coined them. 
Whether the terms are used honestly 
and properly or ignorantly and fraudu- 
lently we can easily ascertain by asking 
the question: ‘‘To what animal is this 
animal linebred?’’ If the user of the 
term does not quite understand what 
it means he will hesitate before reply- 
ing while if he is engaged in misrepre- 
sentation a glance at the written pedi- 
gree will show whether or not the blood 
of a certain animal shows all down the 
line and in every mating. Linebreed- 
ing is only one form of inbreeding. 
A Biography of Luther Burbank 
LUTHER BURBANK: HIS LIFE AND 
HIS WORKS, by Henry Smith Williams, 
M.D., L.L.D. Pp. 333, 40 illustrations, some 
of them in color. New York, Hearst Inter- 
national Library Co., Inc., 1915. 
Mr. Burbank has not been wholly 
fortunate in his biographers, but Dr. 
Williams’ well-made book is at least an 
advance over W. 5. Harwood’s amusing 
performance of 1907. It is entertain- 
ingly written, and can hardly fail to 
create in the layman an interest in plant 
breeding. If the layman then pursues 
his studies, he will quickly get rid of the 
false perspective and inadequate state- 
ments of the problems of plant breeding. 
No one, indeed, need hope to get a 
proper idea of genetics from the book, 
but he may get an interesting account 
of much remarkable work, and in the 
concluding chapters some sensible ob- 
servations on eugenics, although the 
parallels between plants and men are 
too closely drawn. Many of the illus- 
trations are admirable. 
Some Sweet-Pea Hybrids 
What are believed to be the first 
species-crosses on record of the sweet pea 
(Lathyrus odoratus) are described in the 
Gardeners’ Chronicle (London, September 
30), by B. T. P. Barker. The only 
successful one of many attempts was 
with L. hirsutus, which differs little 
from the sweet pea. The first-genera- 
tion hybrids were weakly and somewhat 
intermediate between the two parents; 
the second, third and fourth generations 
showed a little segregation of characters, 
but not much. These hybrids seem 
to have little commercial value, but 
attempts are being made to use them as 
“bridging species’’ for wider crosses. 
