The parents of Agassiz had intended that he should leave school at fifteen, and enter commercial life, for they had never associated any serious meaning with the boy's love for natural history, and the years passed at Bienne seemed a sufficient preparation for a life to be spent at the desk of a man of business. But Agassiz's love for study had grown to such proportions by the time it became necessary for him to leave Bienne that he begged for two years more of student life, and although this called for some self-denial on the part of the parents, who had only a limited income to depend upon, the wish was cheerfully granted, and the boy was allowed to enter the college of Lausanne.

And this step, whose importance no one then conjectured, was in reality the turning-point of the boy's life. Here he heard his first lectures on zoölogy, based upon the teachings of Cuvier and Lamarck, and learned the great importance of system and classifications, and that the greatest authorities could differ in regard to the name and place of the various classes. The view of Cuvier in the "Règne Animal," and of Lamarck in his work on the invertebrate animals, all showed conclusively the importance of anatomy in the study of zoölogy, as their conclusions were drawn chiefly from observations on the structure of the animals, and depended little on other points. Agassiz was thus led to see the great value of anatomy, and his interest in this subject was at once awakened.

Lausanne possessed the only collection of animals in that part of the country, and Agassiz's newly awakened interest was stimulated by the sight of so many specimens hitherto unknown to him; he visited the museum as often as possible, observing and comparing the different varieties with his usual intelligence, and, no longer content with this superficial way of study, ardently began to long to understand the internal structure, so that he might be led to the scientific way of classification.

In this respect he was fortunate in having an uncle at Lausanne, who was a physician, and who lent a willing ear to Agassiz's intelligent questioning. And it was through the influence of this relative that all thoughts of a commercial life for Agassiz were finally abandoned, and he was allowed, when seventeen years of age, to enter the university of Zurich as a student of medicine.

Here Agassiz's real scientific training began, as, for the first time, he came under the instruction of men who were studying nature from her own book, and did not depend utterly on the teachings of others; and this originality was of the greatest benefit to Agassiz at this time.

He entered upon his medical studies with the greatest zest, being delighted with the idea of taking a profession so closely allied to his favorite pursuit of natural history, and as his teachers lent their aid and encouragement, whenever it was possible, his life at Zurich promised to partake more of the nature of a holiday than of a serious working time. His anatomical studies were especially interesting, as in that department he felt that he was not only fitting himself for his work as a physician, but that he was put in the way of following out the suggestions contained in the works of Cuvier and Lamarck, and entering upon a wider field of scientific inquiry than he had been before able to work in.

The first lectures he heard in anatomy roused such an interest that he could think of nothing else, and in speaking of this time afterward he said that he could see nothing but skeletons, and could find no pleasure out of the dissecting-room. With his customary zeal he at once began to make a collection of bones and skulls, dissecting all the animals he could find, and, as was the case at Bienne, turning his rooms into a small menagerie.

A large pine-tree in the corner of the room became the home of scores of birds which flew about the head of the young naturalist while he was busy arranging his collections, and the streams and lakes furnished specimens for a new aquarium, while shells, minerals, and living pets of all kinds, showed that Agassiz had in nowise changed his tastes from those which distinguished him as a child.

A private library at Zurich, to which Agassiz had access, held some valuable works on natural history, and here the young student spent many an hour copying the text and illustrations in his note-books, as he could not afford to buy the necessary text-books. Two volumes of Lamarck's "Invertebrate Animals" were copied at this time, and although this plan of study might appear unnecessarily hard, yet it after all served a good purpose, as it made Agassiz depend less on text-books and more on observation and original research, a thing which could not fail to have a beneficial effect on one who was destined to become distinguished as an independent thinker.

During his two years' stay at Zurich, Agassiz was diligent in his application to the study of medicine, but the love of natural history was gaining greater sway over him year by year, and the books and reports of those naturalists who had enjoyed foreign travel took such hold of his fancy that he, too, became possessed of an ardent desire to travel and study the wonders of nature for himself.

It is not surprising, therefore, that at the end of two years, he persuaded himself and his friends that it was absolutely necessary for him to enter the University of Heidelberg for the purpose of pursuing his medical studies to the best advantage, for there he knew he should find some of the most distinguished naturalists of Europe.

The life at Heidelberg was but a continuation of that passed at Zurich, with the exception that soon after his arrival at his new quarters Agassiz made the acquaintance of a young man who was, like himself, very deeply interested in natural history, and who became his intimate friend almost from the first moment of meeting.

The two friends were together constantly, and studied zoölogy in the fields, woods, streams, fish-markets and museums, each benefiting the other by his experience and advice; for although Agassiz had by this time become familiar with a large part of the animal kingdom his friend Braun was the better botanist of the two, and thus they were able to derive mutual benefits from each other's company. When not abroad botanizing and zoölogizing they spent much of the time in their rooms, where, while one prepared specimens, arranged collections, or dissected cats, dogs, fishes, and butterflies, the other read aloud from some work on anatomy or physiology. His intercourse with Braun proved of the greatest service to Agassiz, who, from that time, ceased to regard the study of living animals as of paramount importance, and began to take a wider view of the aims and ambitions of the naturalist.

The work of Cuvier, and other specialists on fossils, also attracted his attention about this time, and in fact the experience of Agassiz at Heidelberg serviced to so deepen his perception of his own peculiar powers as to make him dream more and more of becoming a naturalist to the exclusion of everything else.

After a year and a half spent at Heidelberg Braun determined to enter the university of Munich, and Agassiz accompanied him. Munich was rich in the presence of several teachers and travelers of distinction, and Agassiz at once felt the inspiration of the new influence. His medical studies grew irksome to him, and his studies in natural history occupied nearly his entire attention, while his visits to the rooms of two of his new friends who had traveled in Brazil, and brought home a fine collection of fishes, awoke anew that love of travel which is the ever-present impulse of the true naturalist.

But travel was impossible at this time, and Agassiz was somewhat comforted for the deprivation, by a proposition from one of his traveled friends to describe the fishes brought back from Brazil. This was work of a character highly suited to the wishes of the young student, and he set about it with enthusiasm, keeping it a secret from his parents as he wished to surprise them with an evidence that his taste for natural history and distaste for Medicine might, after all, lead to some practical end.

Agassiz worked on the Brazilian fishes with an earnestness that well repaid the trust reposed in him, and the first volume appeared in the autumn of 1828, when the editor was in his twenty-second year. The work was well received by all European naturalists, who felt that it furnished a necessary link in ichthyological history, and Agassiz received from Cuvier a letter of warm appreciation of its merits, and the promise to incorporate it into his new edition of the "Règne Animal."

This success so encouraged him that he decided to undertake another work somewhat similar in character, and he therefore began his work on the fishes of Switzerland and Germany.

During his preparation of the "Brazilian Fishes," Agassiz was buoyed up by the hope that he might be included in the list of those who were about to start on scientific tours, hoping either to join Humboldt's expedition to Asia, or a similar excursion to South America under the direction of another naturalist.

He therefore undertook a regular course of training as a preparation for the journey, learning blacksmithing, carpentering, practicing sword and sabre exercises, and taking long walks day after day, loaded down with bags of plants and minerals. This course, he thought, would fit him to endure the disadvantages of travel through uncivilized countries, and it was a bitter disappointment to him to find that he could obtain no place as assistant to any one contemplating foreign travel.

However, he still kept on the path he had marked out for himself, and as a fine opportunity presented itself for studying the collection of fossil fishes in the museum of Munich, he at once undertook the preparation of a work on that subject. It was a fine chance for the young naturalist to show what he could do, as fossil fishes had up to that time received little attention, and it was Agassiz's own originality and vigor of thought that suggested the choice of this topic.

He employed two artists to help him in the work which progressed rapidly in spite of the fact that the author was at the same time engaged on his Fresh-Water Fishes of Central Europe, and hard at work studying for his diploma.