Detailed Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Problem:By the 1890s the profound effect of adrenal extracts on many different tissue types had been discovered, setting off a search both for the mechanism of chemical signalling and efforts to exploit these observations for the development of new drugs. The blood pressure raising and vasoconstrictive effects of adrenal extracts were of particular interest to surgeons as hemostatic agents and as treatment for shock, and a number of companies developed products based on adrenal extracts containing varying purities of the active substance. In 1897 John Abel of Johns Hopkins University identified the active principle as epinephrine, which he isolated in an impure state as the sulfate salt. Industrial chemist Jokichi Takamine later developed a method for obtaining epinephrine in a pure state, and licensed the technology to Parke Davis. Parke Davis marketed epinephrine under the trade name Adrenalin. Injected epinephrine proved to be especially efficacious for the acute treatment of asthma attacks, and an inhaled version was sold in the United States until 2011 (Primatene Mist). By 1929 epinephrine had been formulated into an inhaler for use in the treatment of nasal congestion.
Solution:
Who identified the active substance?