It was in this field, and not in literature or philosophy, that Greg's interests were most actively aroused during his university career. When his life as a student came to an end, he returned home with his whole faculties of curiosity and enthusiasm concentrated upon natural history, phrenology, and animal magnetism. 'I have a canine appetite for natural history,' he told his brother in 1828. He describes with all the zeal of a clever youth of nineteen how busily he is employed in macerating skulls, dissecting unsavoury creatures before breakfast, watching the ants reduce a viper to a skeleton for him, and striving with all his might to get a perfect collection of animal and human skulls. All this, however, was rather an accidental outbreak of exuberant intellectual activity than serious and well-directed study. He was full of the vague and morbid aspirations of youth. As for me [he writes to his elder brother], I am pining after change, I am thirsting for excitement. When I compare what I might be with what I shall be, what I might do with what I shall do, I am ready to curse myself with vexation. 'Why had I, who am so low, a taste so high?' I know you are rather of a more peaceful and quiet temper of mind than I, but I am much mistaken, if you have not much of the same desire for some kind of life more suited to man's lofty passions and his glorious destiny. How can one bear to know how much is to be seen and learned, and yet sit down content without ransacking every corner of the earth for knowledge and wonder and beauty? And after all, what is picking a few skulls (the occupation which gives me the greatest pleasure now), when compared with gaining an intimate and practical acquaintance with all the varieties of man, all the varying phases of his character, all the peculiarities of his ever-changing situations?'[2] [Footnote 2: August 28, 1828] We may smile at the youthful rhetoric, as the writer proceeds to describe how shameful it would be to remain inactive in the sight of exertion, to be satisfied with ignorance when in full view of the temple of knowledge, and so forth. But it is the language of a generous ardour for pure aims, and not the commoner ambition for the glittering prizes of life. This disinterested preference remained with Greg from the beginning to the end.