60 
PROCEEDINGS OF SOCIETIES. 
from the same locality were also shown by Mr. Molineux. On the 
motion of the Kev. Jas. Jefferis, it was resolved to have a dredging 
excursion on the 18th current. 
San Francisco Microscopical Society. 
The regular meeting of the San Francisco Microscopical Society 
was held on Thursday evening, April 20, with a fair attendance of 
members. 
Dr. Blake presented a slide, mounted with gold, which he had 
obtained from so-called telluride of gold, by treating with acid. The 
telluride was obtained from the American mine, Sunshine District, 
Colorado, and showed no gold before the application of acid, and 
Dr. Blake stated his belief that the pure gold was simply concealed by 
a superficial coat of tellurium. 
Mr. Hanks exhibited two photographs of blood-corpuscles, each 
being from a slide with the blood of a dog and a cat, mounted in 
juxtaposition with that of a man, in order to show at a glance the 
relative size of the globules. The photographs showed a distinct 
difference between the disks of the cat's blood and that of man, but no 
appreciable difference in the case of the dog's blood. 
Dr. Blake exhibited some blood obtained from a rabbit after the 
introduction of sulphate of thorium into the blood-vessels. Although 
the quantity used was only a grain, yet the physical properties of the 
blood had been very much altered, the blood-corpuscles having 
entirely lost their natural form, and presenting an indented outline, 
with numerous small highly refracting dots at the circumference. 
This marked influence on the blood-corpuscles tends to explain the 
highly poisonous character of the salt, death taking place in two 
minutes after the introduction of the above minute quantity into the 
circulation. 
