146 UTILIZATION OF MINUTE LIFE. 



East as late as the eleventh century, at which epoch 

 it still existed in all its vigour. The process em- 

 ployed and the manner of taking the snails has 

 been described by an eye-witness, Eudocia Macrem- 

 bolitissa, daughter of the Emperor Constantine VIII. 

 Her book is to be found in the first volume of the 

 collection published in 1781 by M. d'Ansc de Vil- 

 loison, entitled " Anecdota Graeca," etc. The pro- 

 cess was as follows : A quantity of Gasteropoda 

 were pounded in a trough, and to the mass thus 

 produced was added either a quantity of urine in a 

 state of putrefaction, or some water in which a 

 certain number of the pounded snails had under- 

 gone putrefaction. The cloth was soaked in the 

 liquor produced by this mixture, and acquired a 

 purple colour on being exposed to the air ; some- 

 times it was warmed a little, to accelerate the 

 production of the colour. 



Jacobson and De Blainville found uric acid in 

 these snails, as a product of the so-called saccus 

 calcareous, an organ which secretes uric acid in 

 snails and other Mollusca.* Now, Dr. Prout formerly 

 transformed uric acid into a purple colour of great 

 beauty, which he termed purpurate of ammonia, and 

 which Liebig has since called Murexide. It appears 



* This organ is supposed to be the first vestige of a kidney. 

 See Jacobson in " Journ. de Phys.," xci. 318 ; and compare Carus, 

 " Comp. Anat.," torn. i. p. 377, fr. ed. 



