VOL. LXVI.] PHILOSOPHICAL TRANSACTIONS. 03 



effects of lightning on the white hair of a bullock, is extremely curious, but 

 seems difficult of solution. Whether it can be explained from the difference of 

 texture between red hair and white, is doubtful ; or whether there is not some- 

 thing peculiar in colours, as being conductors or non-conductors of electricity, 

 may deserve inquiry. The phlogiston, or inflammable principle, is thought to 

 be the foundation of colour in bodies, and to abound in proportion to the in- 

 tensity of the colour. But phlogiston and the electric fluid are probably the 

 same, or at least modifications of the same principle ; therefore red bodies are 

 perhaps replete with electric matter, while white bodies may be destitute of it.* 

 A body saturated with it cannot receive more, and may escape, while a neigh- 

 bouring body, not calculated to receive it, may, on its admission, be destroyed. -|- 

 Or there may exist a chemical affinity between electricity and the different rays 

 of light, which, in attracting some, and repelling others, may be the foundation 

 of many curious phenomena. But, while we admire the effects, the habitudes 

 and modus operandi of these subtile fluids may perhaps for ever elude the cog- 

 nizance of our senses." 



XXX. Of the Light produced by Inflammation. By George Fordyce,^ M. D., 



F. R. S. p. 504. 



When a body is heated to a certain degree, it becomes luminous, and is said to 



* Many substances must certainly be excepted from tliis rule. W. Henlv. — Orig. 



f This effect of lightning generally happens to such bodies which, in some measure, resist its en- 

 trance, &c. merely on account of their being imperfect conductors. W. Henly. — Orig. 



1 This distinguished philosopher and physician was born at Aberdeen, in 1736, and died in Lon- 

 don of a dropsical affection in 1 802. After tlie usual elementary instruction at a grammar-school, he 

 was sent to the college at Aberdeen, and from thence, at the age of 15, he went to England, and 

 was received as a pupil, by his uncle. Dr. J. Fordyce, who practised physic at Uppingham, in 

 Northamptonshire. With this relation he remained several years, and then removed to Edinburgh, 

 for the further prosecution of his studies in physic. He took his degree at that university in 1758 or 

 1759. After tills he went to Leyden, and on his return to England, he resolved to settle in London. 

 As he had expended the whole of his patrimony on his education, and had acted contrary to the 

 wishes of his relatives and friends, in choosing the metropolis of England as the place of his residence, 

 he felt that every thing depended ©n his own abilities and exertions. Thus circumstanced, he began 

 to deliver a course of lectures on chemistry ; and the emolument he derived from this source, induced 

 him a few years afterwards to lecture on the materia medica and practice of physic, also. Before 

 this period, no other lectures, appertaining to die profession of physic, beside those on anatomy, had 

 been delivered in the metropolis : Dr. F. may therefore be considered as one of the founders of the 

 London Medical School, having first set tlie example of publicly communicating instruction on three 

 very important branches of medical study, without a knowledge of which anatomy is of no avail • 

 namely, the materia medica, pharmaceutical chemistry, and die history and treatment of diseases. 

 This example originated in Dr. F. and has since been followed by many other physicians, in Lon- 

 don, with no less credit to themselves than advantage to their pupUs. 



•. In 1765, Dr. F. was admitted a Licentiate of the College of Physicians, and about 5 years after 

 he was chosen physician to St. Thomas's Hospital. In 1776, he was elected f. r. s. and in 1787 he 



