GLANDS. 119 



ducing crisping, or irregular contraction of the meshes of the matrix, 

 which consequently constrict the tubes and the Malpighian bodies." 



" Thickening and induration of the matrix may produce injurious 

 effects otherwise than by constriction of the tubes and Malpighian 

 bodies. The minute vessels and capillaries pass through the sub- 

 stance of the fibrous rings. Consequently, induration and contrac- 

 tion of the matrix, by direct pressure on the vessels, must greatly 

 interfere with the circulation, nutrition, and secretion of the kidney, 

 and thus various morbid products, as blood, albumen, pus, tubular 

 casts, etc., may be found in the urine." Pp. 418-429. By isolation 

 of portions of the matrix by repeated washings, and the subsequent 

 application of dilute acetic acid and other reagents, it was found to 

 consist entirely of fibres, containing elongated fusiform nuclei ; in 

 other words, to be pure connective, or white fibrous tissue the 

 yellow elastic element being invariably absent. 



"From the foregoing remarks, it is evident that a correct know- 

 ledge of the fibrous matrix is of great importance, and that its 

 microscopical and chemical investigation, in all cases of diseased 

 kidney, would probably furnish interesting and valuable results." 

 P. 431. 



It remains to notice the original and very ingenious methods of 

 preparing the specimens by means of which Dr. Isaacs succeeded in 

 attaining such successful results. His aim was to render the sub- 

 stance of the kidney transparent under the microscope, and to effect 

 this he instituted numerous experiments with chemical reagents, and 

 "at length arrived at the knowledge of certain processes, which 

 have not only been useful by giving transparency to small portions 

 and thin sections of the organ, but have often enabled them to be 

 viewed both as opaque and as transparent objects." With these 

 processes, all the usual means, such as injections, etc., were also 

 employed. The following, in addition to those already indicated, 

 are the modes of preparing microscopical objects which he praises 

 most highly. 



To show the epithelium of the urinary tubes ; their sections, or 

 scrapings of the kidney, should be kept in a solution of albumen in 

 fresh urine. "To view the tubes of the kidney in their normal con- 

 dition very thin sections, or scrapings of the cut surface of the organ, 

 may be put into a test-tube with water, agitated for a few minutes, 



