210 THE DISEASES AND DISORDERS OF THE OX. 



bovine tubercular bacilli. These bacilli do not so readily kill 

 rodents when exposed to the influence of ozone. This agent, 

 ozone, has, however, sjeraed to be more antagonistic to putre- 

 factive bacilli than to the bacilli of disease. 



To those who hope for great discoveries in the region of medi- 

 cine, and to those who, while knowing what great strides have 

 recently been made in the scope of our powers over disease, 

 whether by therapeutic appliances or hygienic measures, or other 

 modes of preventing and combating the maladies to which 

 animals are subject, such as preventive inoculation, look for still 

 greater powers soon to be gained, the fact that the salt known as 

 perchJoride of mercury, or as corrosive sublimate, has the pro- 

 perty of actually killing the bacilli of various diseases, such as 

 anthrax and tuberculosis, will be hailed with rejoicing. Even 

 the most pessimistic cannot but see in this recent discovery, as 

 in many others made quite lately, that the grand march of 

 science is nowise either less quick or less sure than in the days 

 of Bacon, of Newton, and of other great masters. Nay, rather 

 would we compare its onward progress. to tlial of the children's 

 snowball, which, unlike the rolling stone said to gather no moss, 

 grows larger and larger, and with each successive revolution 

 adds still a greater quantity of snow than with the last. Thus 

 is it with science, the great lever by which human beings may hope 

 not only to remove a great deal of the mystery wrapped up in 

 life, but also to live in the best way possible, and so do their 

 duty, so far as it is shown to them, for the brief space during 

 which they are, for some unknown though doubtless great pur- 

 pose, sojourners upon the face of the earth. 



Before, then, we proceed to the consideration of the causes of 

 tuberculosis, we now propose here very briefly to mention 

 the valuable results which Dr. Klein and Mr. Lingard 

 have quite recently obtained regarding the action of perchloride 

 of mercury on the bacilli found in tuberculosis. A solution of 

 this salt in the proportion of 1 part in 960 parts of water 

 Completely destroys the infective power of the virus of human 

 tubercle, if this is exposed to it for from four to eight hours. If 

 bovine tubercular matter is exposed to the action of the same 

 solution for five hours, and if then tuberculosis is produced 

 by the matter so acted upon^ there is a marked retardation 

 of the disease. Tn one case exposure to the solution for eight 



