278 MR. CROOKES' OBSERVATIONS 



Absolute immunity was hardly to be expected now 

 therefore. 



Put together on the I5th of February, the dis- 

 eased one died on the 2ist, and was replaced by 

 another diseased animal ; but it was not until a month 

 had elapsed that the healthy animal showed any 

 symptoms of illness, and then only in a very mild 

 form, recovering in a few days. Now, allowing nine 

 days for the period of incubation, this experiment 

 clearly shows that by the free use of carbolic and 

 sulphurous acids absolute immunity from contagion 

 was ensured, and that when the animal under so 

 severe a test did succumb, the disease was deprived 

 of its malignant character. 



A case is recorded by Mr. Crookes, in which the 

 cattle plague was communicated to a herd of cows 

 by the carelessness of a cowman, who, having attended 

 a post mortem examination of some beasts dead of 

 cattle plague on a neighbouring farm, went directly 

 afterwards to Mr. Lowe's houses and milked some of 

 the cows. Every one of the cows the man touched 

 died. The liberal use of carbolic acid prevented the 

 others from falling victims. 



Crucial Experiment of the Vahie of Carbolic Acid, 

 A crucial experiment of immense value supplied by 

 accident, but none the less satisfactory and decisive, 

 was tried by Mr. Crookes on a grand scale, on a 

 farm, the very hot bed of cattle plague. The cattle 

 were divided into two lots, 45 in disinfected houses, 



