422 LECTURE XVII. 



have a grey, translucent, sometimes slightly wax-like 

 appearance ; but this, however, is so little characteristic, 

 that no inference can with certainty be drawn from it 

 with regard to the internal changes, and the only possi- 

 bility of determining the point, when one has no mi- 

 croscope at hand, consists in the direct application of the 

 test. One need only brush a little iodine upon the 

 surface, and a number of densely aggregated, yellow- 

 ish- or brownish-red spots are soon seen to start up, 

 whilst the interjacent mucous membrane merely looks 

 yellow. These red points are the villi of the intestine, 

 and if one of them be placed under the microscope, the 

 walls of the small arteries and even of the capillaries, 

 which ramify in them, and sometimes also the parenchy- 

 ma, are seen to be coloured iodine-red. 



The most important disturbances of this kind with 

 which we are as yet acquainted, are those which arise in 

 the kidney. A large proportion of the cases of Bright's 

 disease, especially of the chronic ones, are assignable to 

 this change, and must therefore be separated from many 

 other similar forms as constituting a special, altogether 

 peculiar affection. Kidneys affected in this way were 

 called in Yienna, at a time when the chemical reaction 

 was not yet known, lardaceous kidneys (Specknieren). 

 I must however again remark that it is impossible to 

 distinguish immediately with the naked eye, whether 

 this particular change has taken place or not, and that a 

 part of the so-called lardaceous kidneys exhibit nothing 

 more than a kind of induration. Not until iodine has 

 been employed can a diagnosis be readily made. If a 

 solution of iodine be applied to a quite ansemic cortex, 

 a number of red points usually first appear which cor- 

 respond to the glomeruli, and sometines fine streaks also, 

 which are the afferent arteries ; and next to this, when 

 the disease is very severe, red parallel lines are also 



