K. F. Meyer 447 



First and foremost is the intracytoplasmic multiplication of the bacteria in 

 the epithelium of Bowman's capsule and the convoluted tubules. It was 

 thought that the propagation took place in necrotic cells, but, on closer 

 scrutiny of many sections, invasions and viability were equally present in 

 cells Avith intact vesicular or dense nuclei. In fact, the peculiar intracellular 

 giowth differs in no way from that first described by Theobald Smith^" in the 

 chorionic epithelium of the calf, or of the goat (Meyer*"), and more recently by 

 Goodpasture and Anderson" and b) Buddingh and Womack'" in the vascular 

 endothelium and cells of mesodermal origin of the growing chick. These 

 authors justly concluded that the ectodermal epithelium and mesodermal 

 cells serve as suitable host cells and media for invasion and propagation for 

 Br. abortus and Br. suis. Experiments of a similar nature conducted with the 

 Br. suis strain isolated from D.S., and two years before the paper of Buddingh 

 and Womack had appeared, amply confirmed the observations of Goodpasture 

 and Anderson, but revealed the important fact that the endothelial cells lin- 

 ing the columns of hepatic cells and the glomeruli of the nephros in the 

 embryos sacrificed on the fourth day were frequently crowded with specific 

 bacteria as intracytoplasmic inclusions. The microscopic pictures were in- 

 distinguishable from those seen in the human renal cells. This selective intra- 

 cellular parasitism in mesenchyme cells of various organs is doubtless of 

 greatest significance in the pathogenesis of Brucella infections. 



Up to the present time, the available observations on undulant fever have 

 indicated neither the portal of entry of the Brucella organisms into the tissues 

 of the animal or human host, nor the sites of multiplication of these organisms 

 after in\ asion has taken place. There is no proof that brucellas multiply in 

 the blood stream, although they will grow freely in necrotic tissue (chick- 

 chorion allantoic membrane; abscesses in lymph nodes and epididymis of 

 guinea pigs). Their presence in macrophages and polymorphonuclear leuco- 

 cytes is justly attributed to phagocytosis, there being some indications that 

 under certain conditions even the cytoplasms of these cells may serve as a 

 medium for propagation. Little attention has been paid to the possibility that 

 the epithelial cells of the proximal convoluted tubules of Bowman's capsule, 

 and of the chorionic epithelium may possess phagocytic power. For the locali- 

 zation in the latter, Theobald Smith believes that the bacilli pass from the 

 blood vessels into the uterine cavity where they are rubbed into the substance 

 of the cell by pressure. Once in the cytoplasma, they find conditions favorable 

 for multiplication and protection against phagocytosis. As far as the renal 

 localization is concerned, two possibilities may be envisioned: {a) the bacilli, 

 which pass the glomerulus without causing visible damage, may be pressed by 

 the urinary filtrate into the epithelial cells, or {b) since a peculiar group of 

 renal cells-the lining of Bowman's capsule and the proximal end of the con- 

 voluted tubes-are involved, the possibility of an end result of an excretory 

 function should not be overlooked. The visible phenomenon of intracyto- 

 plasmic parasitism in the epithelium may be the residt of "resorption" or 



