By mental instinct, however, Darwin soon found himself studying marine zoology and other branches of natural science.  This was in a large measure due to his intimacy with Dr. Grant, who, in a later article on Flustra, made some allusion to a paper read by Darwin before the Linnean Society on a small discovery which he had made by the aid of a “wretched microscope” to the effect that the so-called ova of Flustra were really larvae and had the power of independent action by means of cilia.

During his second year in Edinburgh he attended Jameson’s lectures on geology and zoology, but found them so “incredibly dull” that he determined never to study the science.

Then came the final move which, all unknowingly, was to lead Darwin into the pursuit of a science which up to that time had only been a hobby and not in any sense the serious profession of his life.  But again how wide the difference between his change from Edinburgh to Cambridge, and that of Wallace from a month’s association with a working-class Socialistic community in London to land surveying under the simplest rural conditions prevalent amongst the respectable labouring farmers of Bedfordshire—­Darwin to the culture and privileges of a great University with the object of becoming a clergyman, and Wallace taking the first road that offered towards earning a living, with no thought as to the ultimate outcome of this life in the open and the systematic observation of soils and land formation.

But the inherent tendencies of Darwin’s nature drew him away from theology to the study of geology, entomology and botany.  The ensuing four years at Cambridge were very happy ones.  While fortunate in being able to follow his various mental and scientific pursuits with the freedom which a good social and financial position secured for him, he found himself by a natural seriousness of manner, balanced by a cheerful temperament and love of sport, the friend and companion of men many years his seniors and holding positions of authority in the world of science.  Amongst these the name of Professor Henslow will always take precedence.  “This friendship,” says Darwin, “influenced my whole career more than any other.”  Henslow’s extensive knowledge of botany, geology, entomology, chemistry and mineralogy, added to his sincere and attractive personality, well-balanced mind and excellent judgment, formed a strong and effective bias in the direction Darwin was destined to follow.

Apart, however, from the strong personal influence of Henslow, Sedgwick and others with whom he came much in contact, two books which he read at this time aroused his “burning zeal to add the most humble contribution to the noble structure of Natural Science”; these were Sir J. Herschel’s “Introduction to the Study of Natural Philosophy,” and Humboldt’s “Personal Narrative.”  Indeed, so fascinated was he by the description given of Teneriffe in the latter that he at once set about a plan whereby he might spend a holiday, with Henslow, in that locality, a holiday which was, indeed, to form part of his famous voyage.