138 SOME FOOD SUBSTANCES. 



Vogel's Lactoscope. Add milk from a burette by small 

 quantities to 100 cc of water in a 200 cc flask until a sample 

 1 cm thick of the whole mixture held a short distance from 

 the eye in a glass test cell just prevents you from seeing 

 the outline of a candle flame placed 3 feet off. The 

 percentage of cream is ascertained from the number of 

 cc of milk used by consulting Vogel's table (Sanderson : 

 Handbook Physiol. Laboratory, 1873, pg. 531). 



Flesh. Muscle. Take one-quarter beakerful of lean minced 

 beef and half fill the beaker with 10 P>C - solution NaCl. 

 Extract in the water bath at 40 C. for 20 minutes with 

 constant stirring. Strain through muslin. 



1. Test the filtrate for proteids. 



2. Test the reaction, is lactic acid present ? Uffelmann, 

 pg. 142. 



3. Saturate some with MgSO 4 , filter off the globulin and 

 test the filtrate for albumin. 



4. Free some of the extract from proteids by boiling and 

 filtering, and test for phosphates, the most important salt, 

 by adding half a volume of HNO.J and a few drops of 

 molybdate of ammonia heat a yellow pp P 2 O 5 . 



Coagulation of Myosinogen. (Halliburton : Essentials of 

 Chem. Physiology, 1896.) An extract, which is provided for 

 you, is obtained as follows : The blood-vessels of a rabbit 

 which has just been killed are washed out with normal saline 

 through the aorta. The muscles are quickly removed, chopped 

 up small and extracted with 5 1)>c< solution MgSO 4 for 24 

 hours in a cool place. 



5. Dilute some of the extract with 4 volumes of water, 

 and keep at 40 C. in the water-bath. A clot of myosin 

 will form. 



