Deferring for the moment consideration of his scientific work we may take a general survey of Griffith's movements during his working life and of his labours as an explorer and collector.
After spending some months in the neighbourhood of Madras, he was situated for more than two years at Mergui and collected extensively in Tenasserim. He was recalled to Calcutta in 1835 and attached to the Bengal Presidency in order to be sent with Dr Wallich and Mr M'Clelland to visit and inspect the localities in which tea grew wild in Assam. Griffith's full report on this enquiry led to the important economic conclusion (based largely on a critical comparison of the Assam flora with the flora of tea-growing regions of China) that tea might be successfully grown under the conditions in Assam and similar districts of India. When the other members of the expedition returned Griffith was detained in Assam, where he remained during the whole of 1836, making a successful expedition into the Mishmee mountains only once before visited by a European.
Early in 1837 Griffith, accompanied by only one servant, set off on an exploring expedition through the very disturbed country of Burmah towards Rangoon. All news of him ceased, or rather his assassination was credited by the Government and reported in the newspapers, when in June he re-appeared, ragged and travel stained, in Calcutta. He had explored down the Hookhoom (Hokong) Valley and on to Ava, and had then proceeded more rapidly by river to Rangoon, conveying his collections with danger and difficulty.
Appointed Surgeon to the embassy about to start for Bhutan, he filled up the intervening two months by again going to the Khasi hills to collect. He then accompanied the expedition to Bhutan, traversing over four hundred miles of the country and returning to Calcutta in June 1838. Here he spent the next few months arranging his collections and also studying the plants of the suburbs.
In November he joined the army of the Indus and accompanied it in its whole march. He remained another year in Afghanistan making various expeditions in the country and into the Hindoo Koosh. He returned, after visiting Simla and the Nerbudda, to Calcutta in the middle of 1841.