Returning to England in 1839, Gosse was hard pressed to make a living, subsisting on eightpence a day ("one herring eaten as slowly as possible, and a little bread").
His fortunes began to improve when John Van Voorst, the leading publisher of naturalist writing, agreed, on the recommendation of Thomas Bell, to publish his Canadian Naturalist (1840).
The book, set as a conversation between a father and his son (a son Gosse did not yet have), was widely praised.
It is now considered to demonstrate that Gosse "had a practical grasp of the importance of conservation, far ahead of his time."

Gosse opened a "Classical and Commercial School for Young Gentlemen" while keeping detailed records of his microscopic investigations of pond life, especially cyclopidae and rotifera.
He also began to preach to the Wesleyan Methodists and lead a Bible class.
In 1842, he became so captivated by the doctrine of the Second Coming of Christ that he severed his connection with the Methodists and joined the Plymouth Brethren.
These dissenters emphasized the Second Coming while rejecting liturgy and an ordained ministry—although they otherwise endorsed the traditional doctrines of Christianity as represented by the creeds of the Methodist and the Anglican Church.

In 1843, Gosse gave up the school to write An Introduction to Zoology for the Society for Promoting Christian Knowledge (SPCK) and to draw some of the illustrations.
Writing the work inspired him to further his interest in the flora and fauna of the seashore.
He showed in his book that he was a creationist, which was typical of pre-Darwinian naturalists.

In October 1844 Gosse sailed to Jamaica, where he served as a professional collector for dealer Hugh Cuming.
Although Gosse worked hard during his eighteen months on the island, he later called this period his " 'holiday' in Jamaica."
Gosse's study specialized in birds, and Gosse has been called "the father of Jamaican ornithology."
Gosse hired black youths as assistants and especially praised one of them, Samuel Campbell, in his Jamaican books.
For Christian companionship he enjoyed the company of Moravian missionaries and their black converts, and he preached regularly to the Moravian congregation.

On his return to London in 1846, Gosse wrote a trilogy on the natural history of Jamaica including A Naturalist's Sojourn in Jamaica (1851).
It is described as "written in a congenial style and firmly established his reputation both as a naturalist and a writer."

In the field of herpetology, Gosse described several new species of reptiles endemic to Jamaica.
Returning to England in 1839, Gosse was hard pressed to make a living, subsisting on eightpence a day ("one herring eaten as slowly as possible, and a little bread"). His fortunes began to improve when John Van Voorst, the leading publisher of naturalist writing, agreed, on the recommendation of Thomas Bell, to publish his Canadian Naturalist (1840). The book, set as a conversation between a father and his son (a son Gosse did not yet have), was widely praised. It is now considered to demonstrate that Gosse "had a practical grasp of the importance of conservation, far ahead of his time."
Gosse opened a "Classical and Commercial School for Young Gentlemen" while keeping detailed records of his microscopic investigations of pond life, especially cyclopidae and rotifera. He also began to preach to the Wesleyan Methodists and lead a Bible class. In 1842, he became so captivated by the doctrine of the Second Coming of Christ that he severed his connection with the Methodists and joined the Plymouth Brethren. These dissenters emphasized the Second Coming while rejecting liturgy and an ordained ministry—although they otherwise endorsed the traditional doctrines of Christianity as represented by the creeds of the Methodist and the Anglican Church.
In 1843, Gosse gave up the school to write An Introduction to Zoology for the Society for Promoting Christian Knowledge (SPCK) and to draw some of the illustrations. Writing the work inspired him to further his interest in the flora and fauna of the seashore. He showed in his book that he was a creationist, which was typical of pre-Darwinian naturalists.
In October 1844 Gosse sailed to Jamaica, where he served as a professional collector for dealer Hugh Cuming. Although Gosse worked hard during his eighteen months on the island, he later called this period his " 'holiday' in Jamaica." Gosse's study specialized in birds, and Gosse has been called "the father of Jamaican ornithology." Gosse hired black youths as assistants and especially praised one of them, Samuel Campbell, in his Jamaican books. For Christian companionship he enjoyed the company of Moravian missionaries and their black converts, and he preached regularly to the Moravian congregation.
On his return to London in 1846, Gosse wrote a trilogy on the natural history of Jamaica including A Naturalist's Sojourn in Jamaica (1851). It is described as "written in a congenial style and firmly established his reputation both as a naturalist and a writer." 
In the field of herpetology, Gosse described several new species of reptiles endemic to Jamaica.
Philip Henry Gosse