of Edinburgh, Session 1885-86. 
603 
3. The Life-History of the Micro-organisms associated with 
Variola and Vaccinia. An Abstract of Besults obtained 
from a Study of Small-Pox and Vaccination in the 
Surgical Laboratory of the University of Edinburgh. 
By J. B. Buist, M.D., E.B.C.P., Edinburgh. 
“Go to the quality of the active principle ; abstract it from the material, 
and contemplate it by itself. Then determine the time ; how long, at 
furthest, this thing, of this particular quality, can naturally subsist.” — Marc. 
Aurel . , Book ix. sect. 25. 
Origin of Inquiry. 
The following investigations were undertaken with the view of 
ascertaining the nature and cause of opacity in vaccine lymph. 
According to the authorities on the subject, clear fresh lymph is a 
perfect material for vaccination, while opaque lymph, fresh or 
stored, is an imperfect material, but hitherto the nature of the 
difference between them has not been explained satisfactorily. It 
has been maintained by many that opaque lymph is a satisfactory 
material for the purpose of vaccination, but this view is not en- 
dorsed by the National Vaccine Establishment. In April, last 
year, Professor Chiene suggested to me that the cause of opacity in 
lymph was to be found in a “ germ,” and he cordially assented to 
my request for assistance in making the necessary cultivations in 
order to determine its nature. The cultivations detailed were made 
by his assistant Mr Hare, whose intimate acquaintance with modern 
methods of bacteriological research has saved much time and labour. 
The responsibility of the observations recorded rests upon me 
entirely. 
A preliminary microsopic examination of clear and opaque vaccine 
lymph led to no definite result, as the appearances observed could 
not be explained, It was therefore decided to examine — 
I. Empty Commercial Vaccine Tubes for “germs.” 
II. Cultivations of Vaccine Lymph. 
a, By the naked-eye ; b, by the microscope. 
III. Cultivations of Variolous Lymph. 
a, By the naked-eye ; b, by the microscope. 
IV. Clear and Opaque Vaccine and Variolous Lymph. 
V. The Besults of Experimental Vaccination. 
