The method used in this inquiry was to subject anatomically separated parts of the organisms to chemical separations. The means for such separations had to be more gentle than the strong heat and destructive chemicals that had been considered adequate up to then. The interpretation of the new results naturally relied on the general advance of chemistry, the development of new methods for isolating substances of little stability, of new concepts concerning the arrangements of atoms in the molecules, and of new apparatus to measure their rates of change. In the system of chemistry, as it developed in the first half of the 19th century, the new development can be characterized as the turn from inorganic to organic phosphates, from the substance of minerals and strong chemical interactions to the components in which phosphate groups remained combined with carbon-containing substances. [Illustration: Figure 10.--ELECTRIC FURNACE FOR PRODUCING ELEMENTAL PHOSPHORUS, invented by Thomas Parker of Newbridge, England, and assigned to The Electric Construction Corporation of the same place. The drawing is part of United States patent 482,586 (September 13, 1892). The furnace was patented in England on October 29, 1889 (no. 17,060); in France on June 23, 1890 (no. 206,566); in Germany on June 17, 1890 (no. 55,700); and in Italy on October 23, 1890 (no. 431). The following explanation is cited from the U.S. patent: Figure 1 [shown here] is a vertical section of the furnace, and Fig. 2 is a diagram to illustrate the means for regulating the electro-motive force or quantity of current across the furnace. F is the furnace containing the charge to be treated. It has an inlet-hopper at _a_, with slides AA, by which the charge can be admitted without opening communication between the interior of the furnace and the outer air. B is a screw conveyer by which the charge is pushed forward into the furnace. _c'c'_ are the electrodes, consisting of blocks or cylinders or the like of carbon fixed in metal socket-pieces _c c_, to which the electric-circuit wires _d_ from the dynamo D are affixed. The current, as aforesaid, may be either continuous or alternating. _c^{2}c^{2}_ are rods of metal or carbon, which are used to establish the electric circuit through the furnace, the said rods being inserted into holes in conductors _c^{3}_ (in contact with the socket-pieces _c_) and in the furnace, as shown. _g_ is the outlet for the gas or vapor, _h_ the slag-tap hole, and _x_ the opening for manipulating the charge, the said openings being closed by clay or otherwise when the furnace is at work. I use coke or other form of carbon in the charge between the electrodes _c'_, the said coke being in contact with the said electrodes, so that complete incandescence is insured.