Early Organic Chemistry

Abstract

In the early part of the nineteenth century the chemistry of carbon compounds was much less advanced than that of the metals and commoner elements such as sulphur, phosphorus and nitrogen. It was divided into the two groups of Vegetable Chemistry and Animal Chemistry, and in the textbooks of Thomson and Berzelius, for example, we still find the various constituents of plants and animals described without any indication of the real relations existing between their chemical compositions. In Vegetable Chemistry, sugar, acids, gum, indigo, bitter principle, extractive principle, tannin, camphor and indiarubber call for separate description; and in a similar way in Animal Chemistry there are included gelatin, albumin, fibrin, urea, blood, saliva, urine, and the like, mostly from the point of view of medicine or physiology.¹ Such materials were usually called ‘proximate principles’, a name introduced by Fourcroy.² They were known to contain carbon and hydrogen, sometimes oxygen, nitrogen and sulphur, as essential constituents, but the isolation and characterisation of definite substances from them was but little advanced. Many substances could not be crystallised, their purification presented great difficulties, and their analysis was in a very primitive condition. We can therefore understand Wöhler,³ as late as 1835, writing to Berzelius that ‘organic chemistry appears to me like a primeval forest of the tropics, full of the most remarkable things’. The entry into the dark forest, and the clearing of the undergrowth, was a task to which chemists first seriously applied themselves in the period at which we have now arrived, and the discoveries were destined to alter the whole aspect of chemistry.