ANIMAL FLUIDS AND TISSUES. 669 



Muscle pigment. Muscle, even when completely freed from blood, has a red 

 color, due to a pigment which is some slight modification of blood haemoglobin. 



Of non-nitrogenous bodies found in muscle, inosite and sarcolactic acid, which 

 have been previously considered, deserve mention. 



Experiment 78 (Preparation of sarcolactic add). Dissolve 20 grammes of 

 commercial meat-extract in 200 c.c. of water, add basic lead acetate as long as 

 a precipitate is formed ; filter and evaporate filtrate to a syrupy consistence. 

 Then add 200 c.c. of 96 per cent, alcohol ; filter and evaporate the filtrate to 

 dry ness over a water-bath. Dissolve the residue in 40 c.c. of water and 20 c.c. 

 of sulphuric acid. Extract this solution twice with an equal volume of ether 

 in a separatory funnel. Filter the ethereal solutions and evaporate the ether 

 with proper precautions. The residue, consisting of a colorless liquid, is sar- 

 colactic acid, to which apply : 



Uffelmann's test for lactic acid. To an aqueous solution add a few drops of 

 Uffelmann's reagent (10 c.c. of a 2 per cent, solution of carbolic acid in 

 water, to which a few drops of ferric chloride solution have been added). A 

 yellow color is produced. 



Inorganic constituents of muscle are chiefly mono- and dipotassium 

 phosphate, with smaller portions of sodium bicarbonate, salts of 

 magnesium and calcium, some iron salts, and traces of sulphates 

 and chlorides. 



Meat- extracts are of two kinds, those from which the proteins and peptones 

 have been removed, and those containing besides proteins large quantities of 

 the basic extractives. Articles of the first class are destitute of nutritive 

 value, and the second derive no nutritive value from the extractive con- 

 stituents. The physiological effect of the flesh bases seems to be in the direc- 

 tion of nerve stimulants, and for this reason they are to be classed with tea 

 and coffee as adjuncts to food, not as true foods. 



The thyroid gland contains iodine in some form of protein com- 

 bination, known as thyro-iodine ; this compound contains 9.3 per 

 cent, of iodine. 



Desiccated thyroid glands, Glandulae thyroideae siccae. Numerous 

 extracts of the thyroid are upon the market. The preparation of the Pharma- 

 copoeia is the cleaned, dried, and powdered glands of the sheep, freed from fat. 

 It is a yellowish amorphous powder, partially soluble in water. 



Thyreoidectin and rodagen are unofficial preparations prepared respectively 

 from the blood and from the milk of animals from which the thyroids have 

 been removed. Their action is stated to be exactly the opposite of that of the 

 thyroid preparations. 



The thyroid gland, and also the adrenals, have some influence on sugar 

 metabolism, which is not yet understood. 



The suprarenal glands contain a substance which has the power of con- 

 stricting the blood-vessels of the body, and thus causing a great but transient 

 rise in blood-pressure. This substance has been found to be methylamino- 

 ethanol-dioxy-benzol, C 6 H 3 (OH) 2 .CH(OH).CH 2 .NH.CH 3 . It is used particu- 



