GLOSSARY. 721 



Bacteria. A class of minute fungi, which occur in all decomposing 

 animal or vegetable substances. 



Bilirubin. The red coloring matter of the bile of man and carnivora. 



Biliverdin. The greenish coloring matter of the bile of herbivorous 

 animals. 



Binocular. Pertaining to vision with two eyes. A combination of the 

 effect of two retinal impressions by means of which the appearances 

 of distance and solidity are arrived at. 



Biology. The science of life. 



Blastoderm. The primitive cellular membrane formed by the segmen- 

 tation of the ovum, in a part of which the embryo is developed. 



Blood pressure. The force exercised by the blood against the walls 

 of the vessels. It is very great in the arteries, and therefore causes 

 a constant stream through the capillaries to the veins. 



Canaliculi. Minute channels which connect the small cell spaces or 

 lacunae of bone with each other, and contain protoplasmic filaments 

 uniting the neighboring cells. 



Carbohydrates. Compounds of carbon, hydrogen, and oxygen, in 

 which the oxygen and hydrogen exist in the proportions requisite to 

 form water. 



Cardiograph. An instrument by means of which the heart's impulse 

 is transmitted, through an air tube, from a tambour on the chest 

 wall to another which makes a record on a moving surface by means 

 of a lever. 



Catelectrotonus. A peculiar electric state of a nerve in the region 

 where a current passing through it leaves the nerve, i. e., near the 

 negative pole. 



Cathode. The negative pole or electrode, i. e., the one by which the 

 electric current leaves a substance through which it is passing. 



Centrifugal. Efferent. 



Centripetal. Afferent. 



Cerebral vesicles. Primitive swellings on the primary neural tube 

 of the early embryo which develop into the brain. 



Chemical elements. Substances which cannot be split up into com- 

 ponents, and therefore are regarded as simple. 



Chlorophyll. The green coloring matter of the cells of plants. It is 

 supposed to be the agent which, under the influence of light, decom- 

 poses carbon dioxide and water to form the cellulose and starch of 

 the plant. 



Cholesterin. A substance occurring in the bile, white matter of the 

 brain and spinal cord, and in small quantities in many other tissues. 

 Chemically, it is a triatomic alcohol. 

 Cl 



