240 



REN. 



large oval space, which contained a Malpighian 

 body, and several smaller meshes in which the con- 

 voluted tubes were packed ; d, Malpighian capsule 

 and tube, tilled with blood from the Malpighian 

 capillaries; e, fibrin ous mould of a urinary tube 

 entangling oil globules, from the urine. 



a portion from the cortical substance.) It is 

 best examined in a thin section which has 

 been macerated in water for a few minutes, 

 so as to wash away the tubes and Malpighian 

 bodies. The matrix then appears in the form 

 of a fibrous network, the meshes of which 

 have, for the most part, a circular outline. 

 The smaller meshes are of pretty uniform 

 size, and are accurately filled by the tubes, 

 each tube in its tortuous course passing 

 through very many of the cells formed by 

 this curious and beautiful structure. The 

 meshes do not occupy any one plane or posi- 

 tion rather than another, but in whatever di- 

 rection the section of the cortical substance is 

 made, the same regular network presents it- 

 self. When the tubes are in situ, they often 

 appear to be mapped out, as it were, into re- 

 gular circular or oval portions ; an appearance 

 which has, doubtless, confirmed some observers 

 in the erroneous notion that the tubes termi- 

 nate in blind extremities. This apparent iso- 

 lation of the different parts of what is in 

 reality a continuous tube, is very much in- 

 fluenced by the condition of the tube itself. 

 In the normal state, the colour of the tubes 

 often contrasts with that of the matrix, which 

 when free from blood is of a whitish colour, 

 so that the tubes are visible through the sub- 

 stance of the matrix, and the observer can 

 trace the continuity of the tube between the 

 different meshes of the tissue. The same 

 observation applies to the tubes when filled 

 with blood ; in some parts of the specimen 

 portions of the tube appear quite isolated, 

 where they are concealed by the overlying 

 matrix (Jig. 150, a a), while in other parts 

 the tubes are more or less distinctly visible 

 through the intervening fibrous tissue (b b). 

 In some parts transverse sections of the tubes 

 are seen, and in other instances a considerable 

 length of tube appears, uncovered by matrix ; 

 this tissue having been removed by the knife, 

 while the tube itself has just escaped the section. 

 In a subsequent part of this article reference 

 will be made to certain pathological changes, as 

 a consequence of which the tubes lose their 

 epithelial lining and become more or less 

 transparent ; and in this condition, when they 

 are packed in the meshes of the fibrous tissue, 

 they have somewhat the appearance of sepa- 

 rate globular or oval cells, and they have ac- 

 tually been described as such by an expe- 

 rienced microscopical observer.* This ques- 

 tion will be fully considered hereafter, the 

 object of the present brief allusion to it being 

 to show the importance of studying the ar- 

 rangement of a tissue which gives peculiar 

 appearances to the parts with which it is con- 



* On Subacute Inflammation of the Kidney, by 

 John Simon, Esq. F. R. S., Med. Chir. Transactions, 

 vol. xxx. 



nected, and a misapprehension of which may 

 lead, as it has led, to serious practical errors. 



Fig. 150. 



Convoluted tubes filled with blood, as seen when 

 packed in the meshes of the matrix, magnified 200 

 diameters. 



The large oval space represented in fig. 149, 

 c y indicates the position of a Malpighian body ; 

 these bodies, as well as the tubes, being accu- 

 rately fitted into meshes of the fibrous ma- 

 trix. The arrangement of the fibrous tissue 

 in the medullary cones is somewhat different 

 from that of the cortical portion. The tissue 

 in this part is more abundant, so that the 

 tubes are separated by it to a greater distance 

 than in the cortical portion of the kidney. 

 The hardness and greater cohesion of the 

 tissue of the medullary cones, as compared 

 with that of the cortical portion, is in great 

 part due to the more abundant fibrous matrix 

 in which the tubes of this part are packed. 

 A transverse section of the cones shows the 

 matrix in the form of circular meshes sur- 

 rounding the tubes, as in the cortical portion ; 

 but on a longitudinal section the rneshes ap- 

 pear elongated, thus corresponding in form 

 with the venous capillary meshes which oc- 

 cupy the substance of the fibrous tissue, and 

 which in this part of the kidney are elongated 

 in the direction of the tubes. There being no 

 Malpighian bodies in the medullary cones, the 

 larger meshes of the matrix which contain 

 these bodies are not present in this part of the 

 kidney. In order to ascertain the relation 

 which the blood-vessels bear to the matrix, 

 it is necessary to examine portions of a kidney 

 which has been artificially injected, or one in 

 which the vessels are filled with blood. It 

 will then be seen, that while the tubes (Jig. 

 151) accurately fill the meshes of the fibrous 

 tissue, the capillary vessels (b b and c), form- 

 ing a plexus which surrounds the tubes, are 

 contained in the substance of the same 

 tissue (c c). When the blood-vessels are 



