TRANSMISSION OF MICRO-ORGANISMS. 331 



route. It is not even necessary to assume that there is any 

 lesion whatever in the placenta or that the epithelium of 

 the foetal villi is destroyed. An experiment by Zuntz 

 shows clearly that particulate material will easily pass into 

 the amniotic fluid from the maternal portion of the 

 placenta, for if indigo-carmine is injected into the veins 

 of the female the dye passes into the amnion leaving the 

 foetus free, and in this very manner anthrax bacilli may 

 pass, and from the amnion gain access to the mouth of 

 the foetus, enter the gut and set up disease by a 

 primary infection of the wall of the intestine (25). An intra- 

 uterine infection, therefore, can occur without lesion of the 

 placenta, though in the majority of cases this structure is 

 primarily infected, and then the foetus, or else haemorrhages 

 of the placenta permit the passage of micro-organisms. 

 However the undoubted fact that micro-organisms can 



o 



penetrate the healthy skin by way of the hair follicles — and 

 the same is possibly true for the epithelium of the urinary 

 tract — must not be forgotten in considering the passage of 

 bacteria across the placenta. This structure may be nor- 

 mal and even then allow the transit of bacteria. Birch- 

 Hirschfeld (15) from researches on the structure of the 

 human placenta as well as that of mice, rabbits and goats 

 considers that the bacilli of anthrax at any rate can 

 traverse the uninjured chorionic epithelium. Moreover in 

 the human placenta and in rabbits numerous processes of 

 the chorion traverse the placental sinuses, and these pro- 

 cesses are normally destitute of epithelium. It was noticed 

 by Max Wolff (16) that anthrax bacilli easily pass if the 

 placenta was crushed or torn, and micro-organisms which 

 exert a necrotic influence on tissues, such as the pyogenic 

 cocci, appear first to destroy the epithelium of the 

 chorionic villi, and then pass through into the foetal 

 blood. In this fluid micro-organisms reach the liver, and 

 it is this organ which, as a rule, is primarily affected, and 

 then the glands in the lymphatics leading from the organ 

 become implicated. The location, therefore, of tubercles 

 in foetal tuberculosis is characteristic, and all observers 

 insist upon this feature in determining whether tubercular 



