After the death of old Martin, the Society received two fine young bears from Mr. Catlin, but they soon died. Their loss, however, has been amply replaced by the three very thriving young animals which have been recently added to the collection. These come from the Sierra Nevada, about 800 miles from San Francisco, and were brought to this country by Mr. Pacton. They were transported with infinite trouble across the Isthmus of Panama, in a box carried on men's shoulders, and are certainly the first of their race who have performed the overland journey. The price asked was £600, but they were obtained at a much less sum; since their sojourn in this country, they have greatly increased in size, and enjoy excellent health. An additional interest attaches to these animals from two of them having undergone the operation for cataract. Bears are extremely subject to this disease, and of course are thereby rendered blind. Their strength and ferocity forbade any thing being done for their relief, until a short time ago, when, by the aid of that wonderful agent, chloroform, it was demonstrated that they are as amenable to curative measures as the human subject. On the 5th of last November, the first operation of the sort was performed on one of these grizzly bears, which was blind in both eyes. As this detracted materially from his value, it was decided to endeavor to restore him to sight; and Mr. White Cooper having consented to operate, the proceedings were as follow: A strong leathern collar to which a chain was attached, was firmly buckled around the patient's neck, and the chain having been passed round one of the bars in front of the cage, two powerful men endeavored to pull him up, in order that a sponge containing chloroform should be applied to his muzzle by Dr. Snow. The resistance offered by the bear was as surprising as unexpected. The utmost efforts of these men were unavailing; and, after a struggle of ten minutes, two others were called to their aid. By their united efforts, Master Bruin was at length brought up, and the sponge fairly tied round his muzzle. Meanwhile the cries and roarings of the patient were echoed in full chorus by his two brothers, who had been confined to the sleeping den, and who scratched and tore at the door to get to the assistance of their distressed relative. In a den on one side was the Cheetah, whose leg was amputated under chloroform some months ago, and who was greatly excited by the smell of the fluid and uproar. The large sloth bear in a cage on the other side, joined heartily in the chorus, and the Isabella bear just beyond, wrung her paws in an agony of woe. Leopards snarled in sympathy, and laughing hyenas swelled the chorus with their hysterical sobs. The octo-basso growling of the polar bears, and roaring of the lions on the other side of the building, completed as remarkable a diapason as could well be heard.