Alexander early showed great fondness for natural history, collecting flowers, plants, butterflies, shells, and stones, so that he was called the "Little Apothecary." He likewise found great delight in drawing. He says of himself: "Until I reached the age of sixteen, I showed little inclination for scientific pursuits. I was of a restless disposition, and wished to be a soldier. This choice was displeasing to my family, who were desirous that I should devote myself to the study of finance, so that I had no opportunity of attending a course of botany or chemistry; I am self-taught in almost all the sciences with which I am now so occupied, and I acquired them comparatively late in life. Of the science of botany I never so much as heard till I formed the acquaintance in 1788 of Herr Willdenow, a youth of my own age, who had just been publishing a Flora of Berlin. His gentle and amiable character stimulated the interest I felt in his pursuits. I never received any lessons professedly, but I used to bring him the specimens I collected, and he gave me their classifications. I became passionately devoted to botany, and took especial interest in the study of cryptogamia. The sight of exotic plants, even when only as dried specimens in an herbarium, fired my imagination with the pleasure that would be derived from the view of a tropical vegetation in southern lands." At sixteen, then, the boy did not know for what he was best fitted in life. How important for young men and women to study themselves, and know their own tastes and capacities! At nineteen he had never heard of botany, and yet he became one of the most distinguished of botanists! The boy also longed to go to sea, not an unusual desire in restless and ambitious natures. But he was frail in body, and gave little evidence that he would ever be able to accomplish any of the things for which he longed. At nineteen he was ready for college, and with his brother entered at Frankfort-on-the-Oder. He gave his time largely to finance and political economy, by his mother's desire, that he might be able to act in some capacity under the government.