1888.] Dr Berry Hart on Separation of the Plaeenta. 435 
was obtained from a case of Caesarean section, Porro’s modification (ftlis nat. 
size). 
The following are some of the measurements : — Length of uterine wall from 
which placenta separated, 2| inches ; length of part of membranes separated, 
inches ; length of separated placental edge, 4 inches (nearly). 
The question now is, How are we to explain such a specimen 1 
I believe that the placenta separated in part in the relaxation follow- 
ing a pain, and that the escape of blood caused further separation, 
owing to the attachment of the membranes at the lower end of the 
posterior uterine wall preventing its escape. 
2. The Pathology of Cystic Ovary. By J. W. Martin, 
M.D. Communicated hy Dr Woodhead. 
3. Histological Observations on the Muscle, Fibre, and 
Connective Tissue of the Uterus during Pregnancy 
and the Puerperium. By T. A. Helme, M.B. Com- 
municated hy Dr Woodhead. 
4. The Air in Coal-Mines. By T. G. Nasmyth, M.B., D.Sc. 
Monday, IQth July 1888. 
The Rev. Dr FLINT, Vice-President, in the Chair. 
The Chairman read a letter from M. A. Suchetet, asking for 
information as to Collectors of Natural History Specimens. 
The following Communications were read : — 
1. Obituary Notice of the late Robert Gray, Vice-President. 
By Dr R. H. Traquair, F.E.S. 
2. On some Relations between Magnetism and Twist in 
Iron and Nickel. By Cargill G. Knott, D.Sc., Professor 
of Physics in the Imperial University of Japan. 
