24G COLOURING MATTERS AND GASES OF PUS. [BOOK I. 



have shewn that the generator of pyocyanin is a species of bacterium, 

 which has the form of a bacillus, and which possesses in addition the 

 property of decompo'sing glycerin in the presence of calcic carbonate, 

 with the formation of hydrogen, carbonic acid, butyl- alcohol and butyric 

 acid. Fitz cultivated the pus-bacillus in a solution of calcium lactate 

 and ammonium chloride, and obtained, in the solution, a colourless 

 reduction-product of the colouring matter, which was only blue on the 

 surface, but which when shaken with air assumed throughout a deep 

 blue colour similar to that of a solution of copper sulphate. These 

 properties of the blue colouring matter agree exactly with those 

 described by Fordos and Llicke. The bacteria which produce it, 

 and which multiply luxuriantly in the cultivating liquid, are small 

 elliptic bodies, from one to one and a half micromiJlimetres in length, 

 and generally occur hi couples. 



It has been asserted by Herapath that indigo-blue occasionally occurs 

 in blue pus. 



Pyoxanthose. 



The above term was applied by Fordos 1 to a greenish-yellow 

 colouring matter, already referred to in the description of the prepara- 

 tion of pyocyanin, accompanying that body, and like it soluble in 

 chloroform. It may be separated from pyocyanin by ether, in which 

 it is more soluble than the latter body. It crystallizes in yellow 

 prisms. It is soluble with difficulty in water, but readily soluble in 

 alcohol, ether, chloroform, bisulphide of carbon and benzol. It is 

 coloured red by acids, and violet by alkalies. 



SEC. 5. THE GASES OF Pus. 



When pus is subjected to the process employed for the extraction 

 of the gases of the blood viz. heated in a Toricellian vacuum it 

 gives off a mixture of carbon dioxide, oxygen and nitrogen, in which 

 the first-named is much the most abundant constituent. 



Ewald 2 , to whom we owe the greater part of our 

 from Ewaid'a knowledge of the gases of pus, has arrived at con- 

 researches. elusions which may be stated briefly as follows : 



1. Fresh pus yields to the Tori3ellian vacuum only carbon 

 dioxide, oxygen and nitrogen, the two latter gases being present 

 in very small quantities. It never evolves hydrogen (as had been 

 asserted by Mathieu and Urbain 3 ), or sulphuretted or carburetted 

 hydrogen. 



1 Fordos, " Recherches sur la mature colorante des suppurations bleues : Pyocyanin 

 et Pyoxanthose." Paris, Compies Rendus, LVI., 1863, p. 1128. 



s< Ewald, " Untersuchungen zur Gasometrie der Transudate des Menschen." Archie 

 filr Anatomie und Physiologie, 1873, pp. 663698. An exceedingly full and clear 

 abstract of this most valuable memoir is to be found in Maly's Jahresbericht, Vol. iv., 

 pp. 421431. 



3 Mathieu et Urbain, Gazette Itebdomadmre, 1871, No. 24, and 1872, No. 21 (quoted 

 by Gautier). 



