HEREDITARY DEFECTS OF DOMESTIC ANIMALS. 
357 
line was frequently changed. The defect was apparently due to 
an arrest in the development of the skull, leaving a portion of 
the brain uncovered and protruding; and while none of the sows 
bred showed any signs of the defect at the time of breeding, and 
may not even have done so when firstborn, they yet transmitted 
to their offspring, generation after generation, a defect which 
compromised the lives of a considerable number. The observa¬ 
tion teaches that close relationship to defective animals, even if 
a parent has been always free from the defect, tends strongly to 
its perpetuation in the particular strain or family. 
The over-development of a part is less common as a heredi¬ 
tary defect, possibly partly because over-development tends more 
strongly to compromise the life of the individual. One of the 
most common of this class of defects is excessive size of the head 
and neck. This is observed in various domestic animals. I re¬ 
call a bull with a very heavy head and neck whose progeny in¬ 
heriting his form, generally caused serious trouble at time of 
birth, the cows requiring assistance in many cases, thus compro¬ 
mising the lives of the young and mothers alike. 
Instances could be multiplied, but all teach the same lesson 
—that defects are transmitted with as great fidelity as good quali¬ 
ties, and that the cure of or recovery from an essential defect 
does not prevent or even lessen the tendency to transmit and 
perpetuate the defect in the offspring generation after gener¬ 
ation. It even teaches us that sound parents springing from a 
defective family tend to perpetuate in their offspring family 
weakness. A sow the offspring of a boar having scrotal hernia 
is unsound for breeding purposes, though the sex prevents her 
unsoundness as an individual. A careful study of antecedents 
of pedigree, should be made of every breeding animal and de¬ 
fects guarded against with as great diligence as good qualities 
are sought. A complete pedigree should show as far as possible 
every defect of ancestors as well as color or trotting speed, milk 
or butter record, and should have proper weight in fixing the 
value of a breeding animal. 
Veterinarians of New York : Do not thoughtlessly 
tall into the trap prepared for you by the Veterinary Service 
Association. 
IT is said that the only auto-truck in operation in New 
York has a capacity of three tons, and its machinery weighs 
eight tons. Evidently there will have to be a reversal of 
weights before it can hope to be popular. 
