434 
Proceedings of the Boyal Society 
a force constantly perpendicular to the cone described by the string, 
and proportional to the rate at which the area of the surface of the 
cone is swept out by the string. The locus of the extremity of e is 
shown to be a sphere fixed in space. 
The problem of Precession and Nutation is next considered, and 
shown to depend on the integration of the very simple equation 
BVaa — AOa = 
(A — B) Sap V ap . 
where M is the mass, and p the vector, of the disturbing body. 
The complete developments of the solutions of these equations 
are reserved for another occasion. 
3. An Investigation into some previously undescribed 
Tetanic Symptoms produced by Atropia in Cold-Blooded 
Animals. By Dr Thomas R. Fraser. 
Authorities in toxicology appear to agree in including convulsions 
among the effects of belladonna and of its active principle — atropia 
— on man. Convulsive and tetanic symptoms would appear to be also 
nearly constantly produced when fatal doses of this poison are admin- 
istered to dogs, rabbits, and other animals, and to various birds. 
The recent remarkable progress of our knowledge of the exact and 
intimate physiological action of various medicinal substances is 
greatly due to investigations that have been made on animals of 
a lower type of organisation ; and, accordingly, numerous observers 
have instituted experiments with atropia on such animals, and, 
especially, on frogs. Hitherto, however, tetanus has not been 
described as one of the effects of atropia-poisoning in cold-blooded 
animals.* 
In some experiments undertaken to determine the minimum 
fatal dose of atropia for frogs, I was surprised to find that increased 
reflex excitability, convulsions, and tetanus occurred, occasionally, 
at a certain stage in the poisoning. Since first observing these 
unexpected symptoms, I have made a number of experiments to 
* Since this was written, 1 have communicated with Dr John Harley of 
London (the author of several important papers on the physiological action 
and therapeutical employment of belladonna), and have had the pleasure of 
learning that he has also observed tetanus, and other symptoms of abnormal 
reflex activity, in frogs during protracted atropia-poisoning. 
