Symptoms. 927 



in the case of a diabetic horse that the urine contained more 

 sugar in the morning than in the evening and that the amount 

 was increased after psychic excitement, while hard work did 

 not cause a diminution in the amount of sugar present. There 

 are cases where, in spite of uniform feeding, the amount of 

 the eliminated sugar does not remain constant, the urine being 

 temporarily free from sugar (diabetes mellitus intermittens) ; 

 if however the disease is far advanced, the glycosuria never 

 ceases entirely. 



For the practical demonstration of grape sugar the fermentation test is best 

 adapted. The simplest way of making this test is as follows: A bit of yeast as 

 large as a pea is added to a test tubeful of urine which is closed with a perforated 

 cork, a U-shaped thin glass tube being inserted in the perforation. The cork is 

 fitted so that no air bubbles remain on the surface of the urine. The test tube is 

 then inverted and permitted to stand at room temperature, or better, near a stove 

 for 24 hours. If grape sugar is present, the action of the yeast produces alcohol, 

 and also carbonic acid which collects in the upper portion of the test tube and 

 forces the urine downward. In order to make quite sure iv'h well to prepare two 

 control test tubes, one of which is filled with normal urine, the other with a solution 

 of grape sugar, to both being added a piece of yeast, in order to determine whether 

 the yeast itself produces carbonic acid and whether it is active. If the fermenta- 

 tion test is positive, grape sugar is surely present. 



For a quantitative test with the fermentation reaction graduated glass tubes 

 or other apparatus must be employed. None of these apparatus, not even Lohn- 

 stein's saecharimeter, is adapted for an exact quantitative test, but they are quite 

 useable for practical work, especially for determining variations in the elimination 

 of the sugar. 



Preller found the reaction with aniline dyes sufficient for practical purposes: 

 10 cc. of urine are heated in a test tube to about body temperature; on adding 

 a small amount of finely ground gentian violet or methylene blue, diabetic urine 

 is colored blue immediately and without shaking. 



A relatively easy test is that of Trommer: One part of ofiicial potassium or 

 sodium hydrate is added to three parts of urine; to this mixture a 10% solution 

 of sulphate of copper is added drop by drop and shaken up until a trace of the 

 precipitate remains on shaking. The upper layer of the mixture is then heated 

 slowly, when in the presence of sugar a yellow or red finely granular precipitate 

 occurs, even before the liquid commences to boil. — Porcher found a modification 

 of Trommer 's test useful: in this the reagent (Fehling's solution) and the urine 

 are boiled in separate test tubes and then the urine is poured carefully over the 

 reagent. 



In human urine physicians have ^exceptionally found levulose, pentose, dex- 

 trin and inosite, besides the grape sugar. There may also be found acetone, organic 

 acids (formic acid, oxybutyria acid, azetoaeetic acid) and albumen, which mostly 

 appears in consequence of a complicating nephritis. (In the urine of a sick horse 

 the authors found very much oxybutyrie acid and azetoaeetic acid; the same 

 was observed by Preller.) 



Another constant symptom is a striking increase in the 

 sensation of thirst (polydipsia), and an abnormally increased 

 appetite (polyphagia) is frequently observed. The mucous 

 membranes of the mouth are dry, the gums at times loosened 

 and sensitive. 



The lens of the eye often becomes opaque (gray cataract; 

 cataracta diabetica) commencing from the center, usually in 

 both eyes and leading gradually to complete blindness; only 

 in isolated cases may the opacity disappear temporarily if the 

 disease is not too for advanced and the animals are fed suitably. 

 Sometimes corneal opacity is met with, possibly together with 

 ulcerations (Heiss), also inflammation of the iris, hemorrhage 

 beneath the retina ot a loosening of the latter. 



