Eastern Bloc countries such as the Soviet Union had high rates of population growth. In 1917, the population of Russia in its present borders was 91 million. Despite the destruction in the Civil War, the population grew to 92.7 million in 1926. In 1939, the population increased by 17 percent to 108.
Causes of Chronic Vomiting in Dogs Chronic vomiting can be caused by diseases of the gastrointestinal tract or can occur secondary to other systemic diseases. It is important to try to establish the cause of chronic vomiting.
Thinkstock/Comstock/Getty Images. An upset stomach is the most frequent cause of a dog vomiting white foam. Sometimes, dogs cough up a thick and foamy, white vomit when they eat too fast, ingest inedible material like dirt or weeds, drink water too fast, or just finish exercising. Vomiting is simply the bodyâs way of expelling substances that are not beneficial for the dogâs system.