discoverer of Fluorine in the Blood. 165 



of the declaration of Treviranus, that the gastric juice of birds 

 contains hydrofluoric acid ; the final sentence being, " We may 

 now look for fluorine in all the animal fluids." 



I merely name the title of the seventh section, which is headed 

 " Of the presence of Fluorine in Fossil Bones and its relation to 

 Animal Life." 



In the summer of the same year, 1846, I ascertained the ex- 

 tent to which pure water dissolves fluor-spar, namely 0-26 grain 

 in 7000 grains of the liquid at 60° F. This result was announced 

 to the British Association at its meeting for that year, and to 

 this Society in November. In 1849 these observations were 

 repeated with certain variations, to meet objections which had 

 been raised to my conclusions, but with the same result. In 

 1849 I communicated to the British Association the results of 

 a series of analyses, demonstrating by a new method of inquiry 

 the presence of fluorine in the waters of the Frith of Forth, the 

 Frith of Clyde, and the German Ocean; and in March 1850 I 

 communicated to this Society an additional series of observations 

 made in the same way, but extended to the waters of the Irish 

 Sea, of the Atlantic, and the Mediterranean. This paper was 

 accompanied by a letter from Professor Forchamraer of Copen- 

 hagen, testifying to the presence of fluorine in the waters of the 

 Baltic. In the summer of the same year (1850) I returned to 

 the analysis of blood and milk for fluorine, feeling assured that 

 still more decisive proofs of its presence in both could be obtained 

 by using a larger amount of material, and subjecting it to a sim- 

 pler process. Accordingly, employing in the case of blood (which 

 was that of the Ox) 26 imperial pints, in the case of milk 9 im- 

 perial pints, and in that of cheese 12 lbs., I was able to etch 

 glasses with the hydrofluoric acid evolved from them so deeply 

 that they might have been printed from, like copper plates. The 

 etched glasses were shown to the members of the Chemical and 

 Physiological Sections of the British Association at its meeting 

 in Edinburgh in 1850, and the details of the process published 

 in its ' Transactions,' as well as in the Edinburgh Philosophical 

 Journal for October of that year*. In the spring of 1852 I 

 again brought the subject before this Society in a paper entitled 

 "On two new Processes for the Detection of Fluorine when 

 accompanied by Silica ; and on the presence of Fluorine m Gra- 

 nite;, Trap, and other Igneous Rocks, and in the ashes of recent 

 and Fossil Plants." (Head April 19, 1852.) In the summer also 

 of the same year, a communication, founded on an application of 

 these processes, was made to the Botanical Society of Edinburgh, 



* They are specially referred to in the English translation of Lehmaun's 

 ' Phvsiological Chemistry,' by Prof. G. E. Day, vol. i. p. 425. Cav, Soc. 

 Publ. 1H51. 



