Pasteur showed that the failure of the silkworm was not due to one disease, but to two diseases--pebrine and flacherie. These diseases are communicated to the eggs of the worms, so that the young begin life handicapped by the maladies. The crawling of the worms over leaves and stems makes these liable to communicate the diseases. The prevention of the diseases is accomplished by procuring absolutely healthy eggs and then never letting them come in contact with anything that may have been touched by diseased worms. If, at the egg-laying period, worms show any signs of disease their eggs are to be rejected. These simple suggestions were the result of rigid experimental demonstration of the spread of the diseases from worm to worm, including the demonstration of the microbic causes of the two diseases. These precautions proved effective, {308} but their introduction met with opposition. The strain of the work and the worry of controversy brought Pasteur to the brink of the grave by a paralytic stroke. From this he never entirely recovered and was always afterward somewhat lame. After the severest symptoms had passed off he was given the opportunity to make a crucial test of preventing the silkworm diseases at the villa of the French Prince Imperial. The products obtained from the silkworms on the estate had, for years, not sufficed to pay for the fresh supplies of eggs obtained from a distance. Pasteur was given full charge of the silk industry on the estate. The sale of the cocoons at the end of the year gave a net profit of 26,000,000 francs (over $5,000,000). This decisive demonstration effectually ended all opposition.