302 
FACTS AND OBSERVATIONS. 
of clay at the moderate thickness of four j^ards, we find that 
under this city alone there lies probably far more than 
303,443 tons, or about 679,712,320 lbs. weight of vanadic 
acid. The present price of this substance in shops where 
chemical curiosities are sold being about one shilling and 
sixpence a grain, or <£32 5s, 6d, an ounce/ 5 As applied 
science is constantly, at the present day, rendering available 
that which at one time was thought nothing worth, so com¬ 
pounds of vanadic acid may possibly hereafter be found useful. 
The Donderobo. —This is the name given by the natives 
of tropical Africa to a fly, whose bite, according to Baron von 
Decken, is as deadly as that of the better-known Tsetse, de¬ 
scribed by Dr. Livingstone, (see Veterinarian, \ ol. xxxi, p. 17), 
but fatal to asses and dogs only. The baron states the effect of 
the poison seemed to be to produce a tubercular deposit, fol¬ 
lowing immediately upon acute imflammation. These flies 
caused serious inconvenience and even danger to the expedi¬ 
tion, by the destruction of the draught asses of the caravan. 
The inhabitants of one of the mountain ranges manifested 
much opposition to their progress, they having a notion that 
the mere presence of a European would prove fatal to their 
cattle. 
Entozoa in the Blood. —At a late meeting of the 
Royal Medical and Chirurgical Society, Dr. John Harley read 
a paper on a malady (haematuria) produced, at the Cape of 
Good Hope and the Mauritius, by a species of Bistoma , which 
he proposed to call Bistoma Capense, Dr. Cobbold observed 
that no one for a moment could doubt that Dr. Harley 5 s 
illustrations represented the ova of the so-called Bistoma 
hcematolium ; in fact, all tended to show that this haematuria 
of the Cape was identical with the well-known Egyptian 
malady. He had also discovered this parasite in the portal blood 
of an African monkey, and it was quite clear to him that 
our fellow-men at the Cape, in the Mauritius, on the banks 
of the Nile, and the monkeys, too, obtained it by swallow¬ 
ing the “ intermediate bearers 55 of the Bilharzia. These 
Cf bearers 55 or “ hosts 55 were small molluscs or aquatic 
animals, inhabiting the African rivers. They contained the 
higher larval states of this parasite, the larvae being intro¬ 
duced into the human body by drinking the African waters 
unfiltered. Our readers will remember, in the “ Transla¬ 
tions 55 by Mr. Ernes, the interesting account given of 
Bacteriums existing in the blood of animals affected with 
splenic apoplexy. 
