On Preventive Inoculation. 



271 



only directly from individual to individual, or by means of their im- 

 mediate belongings. It is the inability of a virus to grow in lifeless 

 nature that communicates to that disease a strictly contagious cha- 

 racter. 



In the second case, provided the surrounding conditions be favour- 

 able to it, the virus will spread widely around the original focus, and 

 the sources from which infection reaches fresh individuals will grow in 

 number rapidly. 



From the point of view of preventive measures, therefore, in diseases 

 like rabies, or syphilis, or small-pox, or leprosy, where infection is to be 

 found in the patient alone, precautions of isolation taken with regard 

 to the sick and their immediate surroundings, must affect directly the 

 prevalence and propagation of the disease ; whereas in typhoid, cholera, 

 or plague, where the patient is only one, and proportionately a limited, 

 source of danger, his isolation, and the destruction of his belongings, 

 leaves unaffected the vast cultivations of infection which are going on 

 in nature besides-. Measures taken for circumscribing the prevalence 

 of an epidemic by isolating and destroying the foci of infection are less 

 likely to succeed in this category of diseases ; attempts at eradicating 

 an epidemic or at protecting individuals by ways which appear effec- 

 tive in merely contagious diseases will be in this case easily eluded ; 

 and the necessity of personal protection by means of a prophylactic 

 treatment will soon be urgently felt and acknowledged. 



Conclusion. Tlie Officers who assisted in the Bacteriological Investigation in 



India. 



My Lord and Gentlemen — Permit me, before I leave this place, to 

 pay a tribute of gratitude for assistance and co-operation in the inves- 

 tigation work in India to the Officers of the Indian and Bombay 

 Governments, to the Director-General of the Indian Medical Service, to 

 Lieut. -Colonel Owen, Major Bannerman, Major Lyons, Major Herbert, 

 Captain Thorold, Captain Hare, Captain James, Captain Vaughan, 

 Captain Maynarcl, Captain Earle, Captain Stevens, Captain Green, 

 Captain Clarkson, Captain Milne, Captain Leumann, of the Indian 

 Medical Service, to Dr. (Miss) Corthorn, Dr. Gibson, Dr. Marsh, Dr. 

 Balfour Stewart, Dr. Ransome, as well as to Dr. W. J. Simpson, Dr. 

 Powell, Dr. Mayr, Dr. Surveyor, Dr. Paymaster, Mr. E. H. Hankin, 

 the distinguished bacteriologist of the North- West Provinces of India, 

 to His Highness the Aga Khan, and to a number of other European as 

 well as Indian gentlemen, happily far too numerous to permit of my 

 mentioning them all. 



