134 
HORN EXPEDITION—ANTHROPOLOGY. 
J>y IjiLshiiien, “Barcoo Rot” is believed to arise from scratches caused by 
JMulga wood {Aauia aneuni), which in their estimation has sjiecially poisonous 
properties. 
I think, however, that there are no real grounds for this unfavourable 
reputation. The fact is that Mulga is the tree by far the most frecjueutly met 
with in Central Australia, at least this is the case between the termination of 
the South Austi-alian railway .system at Oodnadatta and the McDonnell Ranges, 
and for some distance, also, to the east and west. It frequently occurs in thick 
scrubs; its wood is very hard, and when the tree dies the small branches drop oil’ 
with an oblique fracture and leave behind acutely pointed stumps. If, therefore, 
a traveller should get his hands scratched as he protects his head and face while 
he rides through a Mulga scrub, it is many chances to one that it will be from a 
Mulga spike. Gathering firewood, which is frequently dead Mulga, is another 
source of abrasion to the hands and so also the ever-recurring packing and 
unpacking of the “swags” or of the pack-loads of horse or camel. 
Climatic and other conditions no doubt also play their part; for it is to l)e 
remembered that, in winter, the nights are intensely cold on the high land of the 
far interior. To these cold nights succeed brilliant, cloudless, sunny days having 
a maximum temperature of from 75° to 85° F. or more, while during the summer 
the daily heat is intense, very frequently reaching 110°-120°, in the shade, 
for days together. At early dawn, therefore, in winter, one packs up ones 
“swag” with fingers half frozen, and stiff and clumsy in consequence—^^just the 
conditions for the production of abrasions and chaps. In the daytime the backs of 
the hands or wrists, as one rides along, get baked and burnt in the hot sun’s glare, 
and so the processes of chilling and burning succeed one another. The extra¬ 
ordinary dryne.ss of the atmosphere, in these latitudes, moreover, renders the nails 
and skin extremely brittle and liable to crack. Here then are conditions highly 
favourable to the origin of ruptures and abrasions which are so often the starting 
point of the ulcers in question. 
Various circumstances, too, are unfavourable to the healing process, such as 
the constant rubbing off of protecting crusts, the almost unavoidable local 
infection by flies, the usual absence of a suitable proportion of fresh fruit and 
vegetables, and the weailsome monotony, for long periods, of a diet composed 
mainly of salt-junk ; from the jaw breaking hardness of which even the mawkish 
insipidity of “iron clad,” as the tinned meats are termed, comes as a welcome 
change. 
