This rose to the level of a passion, and was constantly revealing itself in unconscious words and actions. Once he told the story of Dürrckheim, a German naturalist, who after close investigation, wrote a monograph upon the cockchafer, a common insect of Europe, which attracted much attention from scientific men. For weeks before he went hard to work he abstained from any kind of food which was stimulating, even coffee, so that he might have full command of his nerves and steadiness of his muscles. He also so supported his person that the beating of his arteries should not interfere with his delicate dissection. Then Agassiz having held up before us this example for our imitation, gave utterance to the following memorable words: “When sitting at the laboratory table, you should give yourselves up to the work exclusively. Never trifle with Nature. The objects we study are the works of the Creator. Even materialists consider them as the works of the highest forces in Nature. A laboratory of natural history is a sanctuary in which nothing improper should be admitted or exhibited. There we are in the constant presence of Nature and its Author. _I can tolerate with less mental agony improprieties in churches._” When the student would come in from the sea with a bowl of newly-captured jelly fish, or some other equally common specimen, he would frequently see Agassiz coming down to the path to meet him. “What have you got this morning?” Looking at them tenderly—although he had seen the like thousands of times—he would exclaim, “Oh, they are beautiful; very beautiful!” This tenderness for animals extended even to those usually considered repulsive. The toads of the island he would frequently handle without a thought of disgust. A live garter snake two feet in length was brought to him in the presence of ladies who manifested their usual repugnance and fear. “Why,” said Agassiz, “of what are you afraid? It can not harm you. See! I will let it bite me.” Then taking the reptile in his hands he suffered it to coil over his wrist, and holding it gently by the neck, put his finger into its mouth. “It does not hurt me nor harm so much as the pricking of a pin. This is a very fine specimen of unusual color. It should be preserved.” He was particularly careful to forbid any wanton destruction of life, or practice of cruelty in the preparation of specimens for dissection. Abundant as the birds were on the island, only the ornithologist was allowed to shoot, and he was restricted to specimens actually needed. Even the nests so profusely scattered were sacred, and those who were engaged in the study of embryology alone were permitted to collect them. Familiarity with all the forms of life had made him exceedingly tender and watchful of their natural rights.