A BRIEF HISTORY OF VETERINARY MEDICINE
1 The history of veterinary medicine has seen tremendous change over the past 100 years. It’s
hard for us to remember that there was a time when cats, dogs, rabbits, and other domestic
animals weren’t cared for by a veterinarian. In fact, it wasn’t until the early 1900s that pets
began to receive medical care more commonly.
The first known veterinary practice came into being in 9,000 BC in the Middle East. Sheep
5
herders used rudimentary medical skills to treat their animals, which included the dogs that
watched over their herds. Thousands of years later, in Egypt between 4,000 – 3,000 BC,
medical treatment of animals became more common, but was still largely undeveloped.
Ancient humans began domesticating cats, fowl, and dogs, and their owners considered
them as members of their household–like many of us do today.
10
In approximately 1,900 BC, someone captured the first written accounts of veterinary
medicine in four sacred Hindu texts. Within these texts, two distinct writings outlined the
fields of human and animal medicine. Millennia later, in 1850, archaeologists discovered
fragments of an ancient veterinary medical textbook made of papyrus. This text covers
15 diseases relating to birds, cattle, dogs, and fish. Horses were the primary focus of ancient
medical care as they were economically important for transportation, agriculture, and trade.
As human medicine flourished and progressed through the last few centuries, so did
veterinary medicine. In the 1700 and 1800s, we discovered treatments for cholera, Typhoid
fever, and tuberculosis. We could then apply those treatments to protecting farm animals
20 from these same deadly diseases.
Despite these advancements, only in the past 30 years has there been a huge shift in
veterinary medicine. We’ve moved away from a focus on medical care only for livestock.
Veterinarians opened thousands of animal hospitals devoted to the care of cats and dogs
and other small pets. These small, furry creatures have moved into our homes and hearts
25 and have family status.
Advancements in veterinary technology and diagnostics continue to improve our ability to
detect diseases early. Wellness and preventive care allow us to give our pets a better chance
of good health and a higher quality of life. Using tools like digital radiology, advanced
diagnostic and surgical equipment, and pharmaceuticals, we are better equipped to
30 successfully treat them and keep them living longer.
Anesthesia and anesthetic monitoring for animals has also made leaps and bounds, making
surgery safer and more effective for our pets. With a better understanding of animal pain,
we are able to manage pain and discomfort in our pets with new medications and alternative
35
therapies.
SUNLIGHT AND PLANT PRODUCTION
Plants have adapted to an extraordinarily wide range of light environments, from the deep
1
shade of rainforest and underwater habitats to the high-radiation environments of deserts
and mountain tops. Exploitation of a wide diversity of habitats is possible because plants
have evolved various mechanisms to optimise their use of sunlight. Many plants also exhibit
great plasticity in their response to changes in light availability within a particular habitat.
5
This potential for acclimation enables plants to exploit more variable environments than
plants with a narrower range of responses to light. Terrestrial ecosystems are both sustained
and regulated by sunlight: sustained in massive ways by photosynthetically active radiation
but regulated in subtle ways by other wavelengths. Wavelengths most effective for
10 photosynthesis occupy a band between about 380 and 720 nm. A wider band from about
350 to 800 nm spans the action spectra for other crucial responses in plant growth and
reproductive development.
These include seed germination, tropisms, morphogenesis, pigmentation, and photoperiodic
15 responses such as floral initiation. The outcomes of these two light-dependent categories
differ by many orders of magnitude in terms of energy flow within a plant community. In
one case, a flow of radiant energy is converted into chemical energy and stored as biomass;
in the other, miniscule levels of radiant energy trigger shifts in gene expression and
consequent developmental responses.
