BACTERIA IN. SECRETIONS. 69 



And the same observations may be made with re- 

 gard to the presence of bacteria in the blood of man 

 and animals destroyed by various diseases. 



Sometimes these germs grow and multiply in a 

 secretion not perfectly healthy, before it has left the 

 gland follicles, and they have been detected in the 

 milk as it issued from the breast, in the saliva, in the 

 bile and urine, as well as in other secretions. It will 

 no doubt be said in all these cases, " the germs have 

 been introduced from without they pass from the air 

 into the orifice of the duct, and thus make their way to 

 the gland. From this point they might readily pass 

 into the blood." But it is more likely they are in the 

 blood and in the tissues at all times. They are met 

 with in the blood especially, in some instances in which 

 there is no reason whatever for concluding they made 

 their way into this fluid shortly before they were found. 

 Nay, little particles may be seen in the circulating 

 fluid which I believe to be these lowly germs, ready 

 to grow and multiply whenever the conditions become 

 favourable. I have seen such particles adhering to 

 the surface of the white blood corpuscles, and also to 

 the red blood corpuscles. In the fibrin of an aneuris- 

 mal clot I have found active bacteria in vast numbers, 

 and have observed the erosion resulting from their long- 

 continued action so very short a time after death, that 

 I feel quite certain they had been living upon the 

 coagulated fibrin, and growing and multiplying during 

 several weeks previously, and yet they had not passed 



