392 
OXIDATION OF IRON. 
most malignant and infectious disease, but that Poland, Galicia, 
Hungary, Transylvania, and Buckowina, will suffer severely from the 
outbreak cannot be questioned. 
With reference to another foreign disease— the smallpox of sheep 
— it may be mentioned that the Government 'measures, which re- 
quired that all foreign sheep should undergo a quarantine of fourteen 
days, or be slaughtered within four days at the port of landing, 
proved most effective in securing the country against the introduction 
of the malady. 
Passing from foreign to home diseases of a contagious nature, it 
may be mentioned that scab in sheep has been exceedingly prevalent 
during the year. This disease is essentially parasitic in its nature — 
the analogue, in fact, of itch in the human subject. It is not difficult 
of cure, and many of the popular remedies are sufficient for the pur- 
pose. These, however, often fail in effecting a cure, as also must the 
best chosen remedies, for want of sufficient care in their application. 
Each sheep, in turn, should be well examined, and the agent applied 
to every spot where the disease is found to exist. In all places where 
“ scabs” are met with, they must be well broken up with the fingers 
before the agent is used, otherwise neither the Arcari , nor their ova, 
will be destroyed. 
OXIDATION OF IRON. 
Dr. F. C. Calvert, in a paper published in Comptes 
Rendus , gives a full description of a series of experiments 
made with the view r to establish precisely the causes of 
and conditions under which iron rusts. The author comes 
to the conclusion that the carbonic acid, as well as the 
watery vapour, contained in the atmosphere concur jointly 
in causing iron to rust. Prof. Chevreul makes the follow- 
ing observations on this subject : — Claude Bourdelin w r as 
the first who observed (in 1683) that ammonia is formed 
when aerated water acts upon steel. In 1720 E. F. GeofFroy 
found that iron rust formed in the air contains moisture and 
ammonia. Yauquelin found ammonia in the specks of rust 
formed upon a chopper, of which it was suspected that it 
had been used for murdering somebody; the presence of 
ammonia in iron rust should, therefore, be cautiously dealt 
with in medico-legal questions. According to Dr. Calvert, 
pure iron does not decompose pure water at the ordinary 
temperature; and, if this is correct, the fact observed by 
Prof. Chevreul, that the white hydrated peroxide of iron 
decomposes water, becomes more interesting. 
