DEFENSES OF THE BODY 131 



ous but not highly intelligent efforts are being made 

 to utilize this principle by advising the rather 

 promiscuous use of milk containing bacteria which 

 form lactic acid abundantly, and are hence regarded 

 as discouraging the growth of life-shortening putre- 

 factive bacteria in the intestine. Although this 

 practice has received the public sanction of Pro- 

 fessor Metchnikoff, it seems destined to excite false 

 hopes and to bring into merited disrepute a proce- 

 dure which, more carefully controlled, is likely to 

 prove of real service in at least some affections. To 

 establish the value of milk or other food fermented 

 by any special bacteria introduced as defenders of 

 the normal flora conditions of the] digestive tract, 

 very prolonged and painstaking investigations are 

 called for, and it is regrettable that premature 

 efforts in incompetent hands should jeopardize a 

 promising measure. It may already be regarded as 

 certain that the Bacillus vulgaricus, which has been 

 so widely advertised, is no specific for the cure of 

 diseases of the intestine or for the prolongation of 

 life. On the other hand, it is true that all of the 

 defensive measures that have been here summarily 

 reviewed and others which have been passed 

 over in silence give us important clews to the right 

 procedure for prolonging human life ; namely, the 

 maintenance of the natural defenses of the body by 

 all habits of life that are conservative of these 

 defenses, and especially by such habits as wholly 

 avoid the entry of injurious bacteria. 



