CHOLULA 483 CHOPIN purging, with violent griping, cramps of the muscles of the abdomen and lower extremities, and great depression of strength. It is most prevalent at the end of summer or the beginning of autumn. ^ Cholera infantum (infants' cholera) is the name sometimes given to a severe and dangerous diarrhoea to which infants are liable in hot climates or in the hot season. It is now beyond question that cholera, or Asiatic cholera as it is usually called, is caused by the growth of a germ. Vibrio cholera}, discovered by Koch in 1883. During epidemics this organism is found in the intestinal canal of healthy persons, as well as cholera patients, so it is clear that the germ alone is not sufficient to cause the dis- ease. Its malignancy appears to depend upon a run-down or weakened condition of the body. If this exists death may follow within twenty-four hours. In a well person the presence of the vibrio may cause no sickness. These cholera carriers, well themselves, but alive with germs, may play an important part in the spread of the disease. It is now gen- erally believed that insects, and partic- ularly flies, are agents in spreading cholera. They infect exposed foods with the vibrio; water and milk also carry infection during epidemics, as well as raw vegetables. Prevention is largely a matter of situation, and the protection from pollution of food, milk and water. Treatment. — A number of sera have been tried as prophylactics and cures. That of Kolle has given some success, but Haffkine's is the best known and probably the most efficient up to date. The latter is prepared by passing cholera germs through a series of rab- bits, and growing the final product on an artificial culture medium. The ar- tificial growth is used for direct injection into the human body. Persons so vacci- nated are somewhat less likely to con- tract cholera than the unvaccinated, and the protection is said to last about four- teen months. Strong's vaccine is pre- pared by spraying artificial cultures over broths, then incubating the latter at body temperatures, and finally filter- ing the product through a Reichel candle (an unglazed porcelain filter worked by a vacuum pump), which extracts all the germs and gives a sterile product for inoculation. The vaccine treatment of cholera, however, is still in the experi- mental stage. CHOLULA (cho-16'la), a decayed town of the Mexican State of Puebla, stands nearly 7,000 feet above sea-level, on the tableland of Anahuac, 55 miles E. S. E. of the city of Mexico. Cortes found in it 40,000 houses and 400 temples, includ- ing the great Teocalli. Now the place only contains 9,000 inhabitants. It was a great center of the Aztec religion. CHONOS ARCHIPELAGO, a group of islands lying off the W. coast of Chile, mostly between lats. 44° and 46° S., and Ion. 74° and 75° W. Two are large, but they are all barren and scantily in- habited. CHOPIN, FREDERIC FRAN9OIS, a Polish composer and pianist, bom near Warsaw in 1810. His musical education began when he was still a mere boy and before he was 9 years of age he played in public. In August, 1829, he gave two concerts in Vienna and his playing was widely praised by many musical celebrities who were present. This was followed by concerts in Warsaw, Munich, and other cities. As a result of the FREDERIC FRANCOIS CHOPIN Russian occupation of Warsaw in 1831 he removed to Paris, which was his home for the next 18 years. During this period he was surrounded by many men and women of genius and talent and he was one of the most conspicuous figures of this circle. During his resi- dence in Paris he wrote and published many important musical compositions. He made also frequent appearances as
