1921.] Dore.—Malarial Infection in the Imported Skylark. 129 
trypanosomes and leucocytozoa are exceedingly common in birds, often 
occurring in conjunction with malarial parasites. The apparent non-exist¬ 
ence of these parasites in New Zealand might be explained if more were 
known of their intermediate hosts, and whether the intermediate hosts of 
these parasites exist in this country. In Australia trypanosomes, leuco¬ 
cytozoa, and filariae found in native birds have been recorded. The 
scarcity of haematozoa is not only restricted to birds, but is especially 
noticeable amongst the reptiles and fishes. Examination of one hundred 
native lizards, comprising three species, showed the presence of Haemo- 
gregarina lygosomarum* in the common skink ( Lygosoma moco). Four 
hundred fresh-water eels ( Anguilla aucMandii) were examined for Try¬ 
panosoma granulosum , and two hundred frogs ( Hyla aurea) for Trypanosoma 
rotatorium, all with negative results. Both these parasites have been 
recorded from practically every other part of the world. 
THORNHILL’S SODIUM-SULPHIDE PROCESS FOR THE 
RECOVERY OF MERCURY, 
As applied to Cinnabar-ore from Puhipuhi.f 
By W. Donovan, M.Sc., Assistant Dominion Analyst. 
Chemically’ considered, the usual process for the recovery of mercury 
from its ores is a very simple operation, which depends on the fact that 
when cinnabar (mercuric sulphide) is heated to a dull red in air, sulphur 
dioxide and metallic mercury are formed, and the latter volatilizes. The 
ore need be broken only to the size of 2 in. to 2J in. cubes, and if the 
operation is conducted in a furnace with a suitable condensing-system the 
mercury is practically all recoverable. In 1914 E. B. Thornhill introduced 
another process, consisting of the solution of the mercuric sulphide in 
alkaline sulphide, and precipitation of the metal with scrap aluminium. 
He found that in the amalgamation of high-grade silver-ores in the 
presence of strong cyanide solution large amounts of mercury, chiefly as 
sulphide, found their way into the tailings, and that this mercury was 
readily recovered by his process. Experimental work has been carried 
out in California (“ Quicksilver in California,” California State Mining 
Bureau) and in New Zealand (C. H. Holland, N.Z. Journal of Science and 
Technology, vol. 1, p. 153) with regard to the application of the process 
to naturally occurring sulphide, and the results have been very encouraging. 
The New Zealand Quicksilver-mines (Limited), who control a mine at 
Puhipuhi, North Auckland, had trouble in 1916 with the condensing- 
system of their furnace, and asked for an investigation of the Thornhill 
process, but only a small amount of preliminary work was done at that 
time. The trouble became more pronounced early in 1920. In addition 
there was a shortage of suitable fuel, and a considerable proportion of the 
* A. B. Dor£:, The Occurrence of Haemogregarina in New Zealand Lizards, N.Z. 
Journ. Sci. 6 Tech., vol. 2, pp. 163-64, 1919. 
t Paper read before the second New Zealand Institute Science Congress, Palmerston 
North, 26th January, 1921. 
9—Science. 
