BBCT. 187.] UKINIFEKOUS TUBULES. 4O7 



kidneys which are not quite fresh ; audit is, therefore, especially 

 necessary to examine the organ as soon as possible after death, 

 avoiding, at the same time, the addition of all substances which 

 may alter its texture in any way. The contents of the epithelial 

 cells consist of the usual round nuclei, together with a large quan- 

 tity of very finely-granular matter; on the addition of water, yel- 

 lowish drops, probably of albumen, readily pass out, but the cell 

 is not otherwise altered. On the addition of acetic acid, the cell- 

 membrane and granular contents first become pale, the cell-wall 

 soon dissolves, and at the same time, the nucleus becomes very 

 indistinct. Lastly, on the addition of caustic alkalies, the nucleus 

 and cell-wall both disappear immediately. These granules I do not 

 hesitate to regard as of a protein substance. Besides these, and 

 the liquid albumen around them, the cells very commonly contain 

 some small dark fat-drops, and more rarely one or two granules of 

 yellowish pigment. 



The straight and tortuous tubules present, along with the above- 

 mentioned general characters, some minor differences. The straight 

 tubules, although at first of considerable breadth (even 0"o6'" to 

 o - i' "), soon become attenuated by subdivisions to o'Oi'", o*oi4'" 

 to o g oi8 ", but increase again as they leave the pyramids to o - 02"' 

 to o'024'". Of this diameter, they enter the cortex, and then 

 increase to 003 3'" in the proper tortuous tubules, becoming again 

 attenuated close to the Malpighian bodies. In the tortuous 

 tubules, the membrana propria is more delicate (o'ooo3'" to 

 - 0004'" in thickness) and more difficult to isolate; whilst, on the 

 other hand, the epithelium is, as a rule, larger here, its cells being 

 o - oo8'" to 0-012'" in breadth, and o - oo4'" to 0'005'" in thickness; 

 whereas, in the straight tubules, the cells are only 0"004'" to 

 0006'" broad, and o'004'" thick. It appears to me, also worthy 

 of remark physiologically, that the cells of the straight tubules 

 contain clear contents, with but few granules ; and hence it happens 

 that in an anremic kidney the medullary substance appears whitish, 

 while the cortex, on the other hand, is yellowish. 



The Malpighian corpuscles possess a very peculiar structure; 

 they are to be regarded as dilated appendages of the tortuous 

 tubules, and contain, imbedded in their epithelium, a compact, 

 roundish, vascular plexus — the glomerulus Malpighianus, which 

 entirely fills their cavity. The proper coat of the tubules is con- 

 tinued as the envelope of these bodies (fig. 169, a), and here it 

 becomes somewhat thickened, reaching o'0005'" to o*ooo8'" in 

 thickness. The epithelium also passes into the capsule formed by 



