Sprung from exact observation of the phenomena of combustion, this theory was able to embrace all important facts known at that epoch. It had within itself both exactness and scope; it has become a system. After fifteen years of strife, its triumph was complete, and it remained unquestioned for more than half a century the master found great disciples to consolidate and develop his work. Nevertheless, a part of the science remained beyond the reach of their efforts, and of the system, which was more especially applicable to inorganic compounds. Or ganie chemistry was at that time limited to the qualitative description of principles extracted from products of vegetable and animal origin. The genius of discovery had indeed amassed a quantity of precious materials but the science, which was to co-ordinate them, was not yet born. The very ele ments of this co-ordination were still wanting, and could be furnished only by the study of the meta morphoses of organic compounds. To discover the atomic constitution of organic compounds, and thereby to explain their properties, and establish their relations, is the object of Organic Chemistry; and this object is attained by determining the nature and number of the constituent atoms of organic compounds, and by studying their modes of forma tion and transformation.