GLOSSARY. ACINI ALBUMEN. 583 



is added to potassa (the oxide of potassium), the chlorine or radical 

 unites with the potassium, while the hydrogen unites with the oxy- 

 gen of the potassa, and forms water. 



ACINI. A term derived from the Greek word signifying a grape-stone, 

 applied to the minute constituent parts of such glands as the kid- 

 neys, having for their general character rounded groups of vesicles 

 containing gland-cells, and opening, either occasionally or per- 

 manently, by a common central cavity into minute ducts. 



ACOTYLEDONOUS. Applied to plants having in a seed no cotyledons 

 or lobes of the embryo, of which ferns and seaweeds are ex- 

 amples. 



ACROGENS. Applied to plants having a stem that grows at the sum- 

 mit, forming a subdivision of the acotyledons, which includes the 

 ferns, the horsetails, the mosses, and liverworts. 



ADIPOCERE. A substance formerly confounded with cholesterine : the 

 fatty matter into which the bodies of animals are converted when 

 decomposed slowly in a moist soil. 



ADIPOSE TISSUE. The tissue, consisting of minute cells, in which the 

 fat is deposited. 



AFFERENT. A word signifying " carrying to," opposed to efferent, 

 " carrying from," and applied to minute vessels and minute nerves. 

 An afferent vessel is a minute vessel going to a glandular organ ; an 

 afferent nervous filament is one going to a central nervous organ. 

 See Efferent. 



AFFINITY, or CHEMICAL ATTRACTION. Applied to the attraction 

 holding together particles of matter different in kind opposed to 

 the attraction of aggregation, which holds together particles of 

 matter the same in kind. The stronger or weaker affinity which 

 particles of one kind have for particles of other kinds is the great 

 source of chemical action. 



AGGREGATE. In clusters. 



AIR-CELLS. The same as the pulmonary cells. The very minute cells 

 of the lungs into which the atmospheric air penetrates by the 

 bronchial tubes or ramifications of the windpipe larger in carniv- 

 orous mammals than in man, in whom they vary from the 200th 

 part of an inch to three times that diameter. 



ALBUMEN (in Botany). The nutritious matter stored up with the 

 embryo in the seed, called also perisperm and endosperm. 



ALBUMEN (in Organic Chemistry). A proximate principle of the 

 vegetable and also of the animal kingdom, having the same com- 

 position in both. In the vegetable kingdom the juice of turnips, 

 carrots, and cabbages becomes turbid when heated, owing to the 

 presence of vegetable albumen ; in the animal kingdom the white 

 of egg, sometimes called ovalbumen, and the coagulum obtained 

 by heating the serum of blood, called at times seralbumen, exem- 

 plify this principle. See p. 305. 



