686 
A. H. BAKER. 
THE TRANSMISSION OF DISEASE. 
By Dr. A. H. Baker, Chicago, Ill. 
A Paper read before the Illinois State Veterinary Medical Association. 
The consideration of this subject launches us into the com¬ 
plex and hypothetical field of heredity, that to discuss in all 
its features would take too much of the time of a gathering 1 
of busy veterinarians who seem in many cases to be loth to 
devote more than a few hours twice a year to the discussion 
of topics of interest to the profession; so, after briefly stating 
the more generally accepted modern theories of heredity, I 
will present for your consideration a few points on the trans¬ 
mission of disease from parent to offspring. 
i he fundamental law ol heredity is that like begets like, 
or at least tends to beget like ; but, using the language of be¬ 
lievers in evolution, the doctrine of which is now very gener¬ 
ally accepted by the scientific world, many deviations and 
exceptions occur, and may be attributed to the influences of 
environment, whether they can be discerned or not, and 
through these new types may be formed, old ones lost, desir¬ 
able peculiarities perpetuated and improved, and, on the other 
hand, weaknesses amounting in many cases to actual disease 
exaggerated by proper or improper mating of breeding-stock. 
1 he natural tendency in nature is toward an equilibrium, 
an evening up of advantages and disadvantages; but if the 
mating occurs between animals possessing the same strong 
peculiarity, the offspring will inherit that peculiarity in an 
exaggerated degree. If the mating occurs with onedn which 
that peculiarity is wanting it will be diminished one-half in the 
offspring, and if kept up through several generations it will 
become obliterated. 
The most common peculiarities that we see transmitted 
are anatomical structure and outline, size, color, intelligence, 
disposition, appetite, speed, strength and endurance. For 
illustrations of the transmission of these peculiarities I will 
refer you to the constant development of the sexual organs, 
the anatomical outlines of the thoroughbred and broncho, the 
