How does everyone show their sympathy for Captain Cook when he is sick?

The next day, Mr. Popper and Captain Cook appear in the Stillwater newspaper, the Morning Chronicle. The story is picked up by the Associated Press, and soon the pair is appearing in newspapers around the country. While Mr. Popper becomes very happy, Captain Cook gets sick, becoming listless and feverish. His coat loses its luster, and he starts to lose weight. The Poppers become worried and call a veterinarian. The veterinarian, while never having treated a penguin, can tell it is quite ill, and he prescribes some pills, though he is not hopeful of recovery. In desperation, Mr. Popper writes to Dr. Smith, curator of an aquarium in a nearby large city. Dr. Smith writes back, stating that the problem might be loneliness, and he has his own penguin that has fallen ill. Dr. Smith sends Mr. Popper his penguin in the hopes that companionship will cure both penguins.