406 INDEX AND GLOSSARY. 



Archeus, 116. In the theory of Yan Helmont, the specific 

 agent presiding over vital functions. 



Archegonium, 155 (Gr. arche, beginning ; gone, seed). The 

 early condition of the spore-case in mosses, ferns, etc. Also 

 called Pistillidium. 



Arteries, 201. Tubes conveying blood from the heart to the 

 capillaries. They have three coats, an outer, middle, and in- 

 ner coat. The inner is epithelial, the middle of unstriped 

 muscle, and the outer of fibrous connective tissue. Thej^ are 

 all supplied with nutrient bloodvessels, the vasa vasorum, and 

 have nerves from the ganglionic and spinal systems. 



Arsenic, Tests for, 110. Arsenious acid. The most com- 

 mon form of cr} T stal is octohedral or tetrahedral, but a right 

 rhombic form may be obtained by sublimation. Protoxide of 

 antimony will also yield by sublimation similar crystals, re- 

 quiring discrimination in cases of poisoning. 



Arthritic deposits, 241 (Gr. arthron. a joint). 



Areolar fibroma, 268. 



Ascaris, 336 (Gr. askeris, a round worm). 



Asci, 154 (Gr. askos, a bottle). A long or roundish spore- 

 case of fungi, containing spores. Called also thecse. 



Ascomycetes, 138. An order of fungi characterized by 

 asci. 



Asellus, 172. A. vulgaris, or water woodlouse, an Isopod 

 crustacean, is interesting to the microscopist since its trans- 

 parency permits a view of the circulation. 



Aspergillus, 136, 325. A genus of Mucedines, forming 

 moulds, as the blue mould on cheese, etc. 



Asterias, 168 (Gr. aster, a star). Star-fish. 



Atheroma, 234 (Gr. porridge of meal). A disease of the ar- 

 teries characterized by a pulpy deposit. 



Atrophy of heart, 242 (Gr. a trophe, not nourishing). 



Avanturine. A mineral sometimes seen in cabinets consist- 

 ing of silex and scales of mica. Artificial avanturine is of 

 glass with crystals of metallic copper scattered through it. 



Amcularia, 169 (Lat. avicula, a little bird). The bird's- 

 head processes of the Potyzoa. 



Bacillaria, 144 (Lat. bacitlum, a little staff). A genus of 

 Diatomaceae. 



