Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
From the teeth pattern and the simplicity of the digestive tract it is certain that the dog belongs to the carnivorous class of animals. The dog is often cited as an animal having a simple digestive tract as compared to the complexity of the ruminant digestive tract and herbivorous animals in general. For this reason it was long believed that the dog was dependent upon an exclusive diet of animal products. However, under domestication, especially in recent years, the dog has been submitted to radical changes in diet and it has been demonstrated that the dog can handle a diet containing large proportions of carbohydrates. Along with this idea many fallacies connected with the nutritional requirements of the dog have been done away with. Instead of being able to live only on a diet of meat he may subsist on a diet very much the same as that of his master.
Wykoff, M. H.
"Nutritional Requirements of' the Dog,"
Iowa State University Veterinarian: Vol. 8
, Article 8.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol8/iss4/8