How disastrous a great drought might prove to the cattle of the Pampas is shown by the records of 1825 and of 1830. So little rain fell that there was a complete failure of vegetation. The loss of cattle in one province alone was estimated at one million. Of one particular herd of twenty thousand not a single one survived. Darwin had many other instances of nature's devastations. After the Beagle sailed from the Plata, December 6, 1833, vast numbers of butterflies were seen as far as the eye could range in bands of countless myriads. "Before sunset a strong breeze sprung up from the north, and this must have caused tens of thousands of the butterflies and other insects to perish." Two or three months before this he had ocular proof of the effect of a hailstorm, which in a very limited area killed twenty deer, fifteen ostriches, numbers of ducks, hawks, and partridges. In the war of extermination that was ever before the great naturalist's eye in South America, what is it that favors a species' survival or determines its extinction? Not only is the struggle between the animals and inanimate nature, the plants and inanimate nature, plant and animal, rival animals, and rival plants; it goes on between man and his environment, and, very fiercely, between man and man. Darwin was moved by intense indignation at the slavery on the east coast and the cruel oppression of the laborer on the west coast. He was in close contact with the sanguinary political struggles of South America, and with a war of attempted extermination against the Indian. He refers to the shocking but "unquestionable fact, that [in the latter struggle] all the women who appear above twenty years old are massacred in cold blood! When I exclaimed that this appeared rather inhuman, he [the informant] answered, 'Why, what can be done? they breed so!'"