LABORATORY EXERCISES. 469 



5. Add a couple of grammes of Witte-peptone to a liter of urine ; 

 then examine the solution as described on page 305. 



Exercise XXXIX. 1. Procure some febrile urine and examine 

 this : (a) for urochrome ; (6) for uroerythrin ; (c) for urobilin. 



2. Procure some typhoid urine between the seventh and the tenth 

 day of the disease and apply Ehrlich's test. Use about 5 c.c. of 

 urine and an equal amount of the sulphanilic acid mixture. After 

 adding the ammonia to form a layer above the urine and acid mix- 

 ture note the color-ring at the zone of contact. Shake the fluid and 

 note the color of the foam ; pour all into a white basin and dilute 

 copiously with water ; note the salmon pink. Repeat the experi- 

 ment with normal urine. 



3. Add a little blood to urine : (a) perform Heller's test ; (b) 

 examine the urine spectroscopically (page 311). 



4. Procure some urine containing haematoporphyrin : (a) examine 

 this spectroscopically ; (6) isolate the hsematoporphyrin and examine 

 its pure solution with a spectroscope (page 311). 



5. With urine from a case of melanotic sarcoma perform : (a) 

 the bromine test ; (b) the iron test (page 313). 



6. Procure bile from a dog or from a human being (at autopsy), 

 dilute with water, and perform the various tests described on 

 page 173." 



Exercise XL. 1. Procure blood at a slaughter-house ; let a por- 

 tion flow directly from the vessel into a saturated solution of sodium 

 sulphate or a 10 per cent, solution of sodium chloride (equal parts) ; 

 receive a second portion in a dry cylinder. Note that in the first 

 portion coagulation does not occur. Observe the phenomenon of 

 coagulation in the second. Prepare also some oxalate plasma 

 and some albumose plasma (page 329). Keep some oxalate plasma 

 on ice and note the separation of the corpuscles on standing. 



2. Determine the specific gravity of human blood according to 

 Hammerschlag's method (page 324). 



3. Determine the reaction of fresh cat's or dog's blood according 

 to Lowy's method, and that of human blood according to Dare 

 (page 326). 



4. Isolate the fibrinogen from about 50 e.c. of plasma by half- 

 saturation with sodium chloride (page 330). To the resulting solu- 

 tion of fibrinogen add a little serum. Note the occurrence of 

 coagulation. 



5. Prepare blood-serum by allowing defibrinated blood (500 c.c.) 

 to stand on ice or, still better, by separating the cellular elements 

 by centrifugation. 



6. From 100 c.c. of serum isolate the serum-albumin fraction 

 and the globulin fraction by means of ammonium sulphate (pages 

 332 and 333). 



A. Note the behavior of the globulin fraction (a) on dialysis 

 (examine the remaining solution for globulins by saturation with 

 magnesium sulphate), (b) on passing a stream of CO 2 through a 



