234 ALFR£D SANGSTER. 



cells ; with well-defined outlines, which come into view 

 momentarily, while focussing with the fine adjustment ; other 

 outlines of the same and other cells appearing at a lower 

 level, the epithelium is coated internally with granular 

 debris. External to the epithelium at h can be seen darkly 

 stained bodies, in some parts oblong, and obliquely placed to 

 the circumference, in other parts quadrilateral or rounded ; 

 these are sections of spindle-shaped cells composing the mus- 

 cular coat. 



These cells being arranged longitudinally on the gland 

 tube and the latter coiling in sharp curves, it is clear that a 

 section which traverses one side of the gland tube in a plane 

 at right angles to the axes of the spindle-shaped muscle- 

 fibres must necessarily traverse the o|)posite wall in a plane 

 more or less oblique to those axes, and this accounts for the 

 appearance seen in the figure, where on one side of the 

 tubule the cells are obliquely divided and a portion of their 

 length varying with the obliquity of the section comes into 

 view. Here and there, more darkly stained, can be seen the 

 transversely or obliquely cut stafi'-shaped nuclei peculiar to 

 unstriped muscle cells. 



External to the muscular coat may be recognised, at c, 

 the membrana propria ; it bears the same hyaline, homo- 

 geneous, appearance that is peculiar to this structure wher- 

 ever it occurs. It is stained darker than the muscle-cells, 

 and in places appears to be prolonged between them, as 

 though they were lying partially within its substance. Sur- 

 rounding the membrana propria, are to be seen the fibre 

 bundles and interfascicular spaces of the connective tissue, in 

 this case widely separated by oedema. In the longitudinal 

 section the same parts may be readily identified, the muscular 

 coat appears very thick, probably a result of pathological 

 change ; it shows faint striation and a few longitudinally 

 divided staff-shaped nuclei. The darkly stained membrana 

 propria appears puckered and very distinct. 



Fig. 1 represents three transverse sections of sweat-gland 

 tubule from the ear lobe of the pig. The single layer of 

 well-formed epithelial cells is seen lining the tubule at a, 

 the outlines of the cells appear more or less cylindrical in this 

 section, their free borders bulging towards the centre of the 

 tubule. The nuclei are round, large, and regularly placed. 



The muscular coat is well seen and the transversely divided 

 stafi'-shaped nuclei are more plainly visible than in the last 

 specimens. The membrana propria, although not so well 

 marked as in the last specimen, can still be recognised as a 

 thin hyaline membrane situated between the transversely 



