The Rabbit Quedion. 29 



the blood of diseased animals, and it is supposed that there 

 is a special one for each form of disease. There is much 

 difficulty ill saying whether it is vegetable or animal. 



It is now nearly forty years since microbes were first noticed 

 by Davaine, but their real importance as factors in disease 

 was not recognised thoroughly until 1877, when the 

 celebrated paper of MM. Pasteur and Joubert was read 

 before the Academy of Sciences. 



These o-entlemen selected anthrax, a disease affecting- men 

 and cattle, callea in the first case " malignant pustule," and 

 in the second " splenic fever," and showed that in the blood 

 myriads of these little organisms were found, either as slender 

 waving rods, or minute oval spores, or as curled filaments ; 

 and also proved that the poison if it existed in these could 

 be cultivated out of the body to an indefinite extent without 

 losing any of its infectious virulence. The method was 

 this : — A neutralised decoction of yeast in water was 

 strained and heated so that all germs in it were destroyed, 

 and a drop of the diseased blood was then placed in it. 

 After a day or two it was full of the microbic growth, and a 

 single drop let fall into a fresh quantity of yeast water 

 produced a second crop, and so on. Of course the latter 

 cultivations give the microbe free from any foreign matter, 

 and it is from these that its form is best studied. Over fifty 

 successive cultivations of the anthrax microbe have been 

 made, and the last one was as virulent as the first. I spoke 

 of the spores of the microbe. While the active form is very 

 sensitive to degrees of heat (the typhoid microbe being very 

 inactive at low temperatures, and the anthrax microbe 

 inactive at high ones), the spores, the seeds as one might call 

 them, which form when the protoplasm of the active plant is 

 drying up, can endure the greatest heat and cold, and could 

 be swept in dust storms from one end of the colony to 

 another, carrying disease and death for thousands of 

 miles. 



This should be borne in mind when we consider the 

 proposal to carry on the experiments "safely" here within 

 walled paddocks. We might as well build a post and rail 

 fence to keep out the cholera, or attempt to enclose small- 

 pox within open wire network. Even an island would not 

 secure safety, for the germs might be blown across, or be 

 carried on a boat, or on the clothes and hair of the 

 experimenters. This is one of the great dangers — once 

 admitted, the disease is practically uncontrollable. 



