GLOSSARY. MANYPLIES MYCELIUM. 599 



MANYPLIES. The same as omasum and psalterium the third 

 stomach in ruminants. 



MARGARINE, MARGARIC ACID. Margarine, one of the proximate 

 principles of oils and fats ; margaric acid, the acid produced in 

 the saponification of margarine. 



MASTICATION. The trituratiou of the food by the action of the teeth. 



MECHANICAL EQUIVALENT OP HEAT. When a pound of water is let 

 fall through the height of 772 feet, it acquires an additional 

 heat of one degree Fahrenheit. The same is true of other bodies 

 falling through the same height. The same is true of any other 

 quantity than a pound. Jf an ounce of water fall through 772 

 feet, its temperature rises one degree Fahrenheit. If a ton of 

 water fall through 772 feet, its temperature rises one degree 

 Fahrenheit. This number, then, 772, is the mechanical equi- 

 valent of heat on Fahrenheit's scale. But a different num- 

 ber must be used under the centigrade scale. If a chilogramme 

 (kilogramme) of water fall through 772 feet, its temperature 

 will rise one degree Fahrenheit. To discover, then, from 

 what greater height a chilogramme of water must fall to raise 

 its temperature one degree centigrade, the following propor- 

 tion will suffice: 100 : 180 : : 772 : 1389.6. But 1389 

 feet are equal to 423 metres ; thus the mechanical equivalent of 

 heat, according to the French system, is 423 metres, by falling 

 through which a chilogramme of water rises through one degree 

 centigrade. 



MECONIUM. The first discharge from the bowels after birth. 



MEDULLA OBLONGATA. The prolongation of the spinal marrow up- 

 wards within the skull. 



MESENTERY. The fold of the peritoneum in which the small intes- 

 tines hang suspended as in a sling, and between the layers of which 

 are their vessels and nerves. 



MESOCEPHALON. A name applied to the tuber annulare or pons 

 varolii : the protuberance between the medulla oblongata and the 

 crura cerebri and crura cerebelli within the skull. 



MIDRIFF. See Diaphragm. 



MITES. See Parasite. 



MITRAL VALVE. The valve which commands the auriculo- ventri- 

 cular opening on the left side of the heart. 



MONOCOTYLEDONOUS. Applied to the great division of plants in 

 which the embryo has but one cotyledon ; this division coincides 

 with Endogenous Plants. 



Mucous MEMBRANE. The membrane which lines all the cavities 

 of the body that communicate with the external air. 



Mucus. A word rather vaguely used, but chiefly to denote the fluid 

 secreted by the mucous tissue, and abounding in epithelial scales 

 detached therefrom. 



MYCELIUM. See Parasite. 



