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358 ACCELLI, GUIDO (1830-1916), Italian physician and politician, was born at Rome 1830, and died at Rome Jan. 11 1916. After graduating in medicine at the university of Rome, he was appointed assistant professor of medical jurisprudence in 1856, and some years later became professor of clinical medicine. He soon acquired a great reputation as a practising physician, being especially noted for the accuracy of his diagnosis, and he devoted himself particularly to the pathology of the heart and to malaria; his studies on the latter subject proved of great value for the reclamation of the Roman Campagna and other fever- stricken zones. In 1875 he was elected deputy for the 3rd Div. of Rome, which he continued to represent until his death. He was Minister of Education in the Cabinets of Cairoli (1879-81), Depretis (1881-7), Crispi (1893-6), and Gen. Pelloux (1898-9), and of Agriculture under Zanardelli (1901-3); from 1889 to 1893 he was vice-president of the Chamber. A keen classical scholar, he took an active interest in archaeological matters, although in some of his projects, such as the famous Passeggiata Archeologica in Rome, he showed more enthusiasm than judgment. His labours for the isolation of the Pantheon and the creation of the Museum of Ancient Art and of the Modern Art Gallery in Rome deserved and met with more general approval.

BACON, HENRY (1866- ), American architect, was born at Watseka, 111., Nov. 28 1866. In 1884 he entered the university of Illinois to study architecture, but in the following year began work in the office of Chamberlin & Whidden, in Boston, where he remained three years. From 1888 to 1897 he was with McKim, Mead & White, in New York, excepting the years 1889-91 which he spent in Europe as Rotch Travel- ling Scholar. From 1897 to 1903 he was a member of the firm of Brite & Bacon, in New York, and thereafter practised alone.

Among his important works were the Court of the Four Seasons at the Panama- Pacific Exposition; the Union Square Savings Bank, New York City; the Public Library, Paterson, NJ. ; the Waterbury General Hospital, Waterbury, Conn. ; and the Whittemore Memorial Bridge, Xaugatuck, Conn. Of numerous monuments, some designed in collaboration with various sculptors, the following should be mentioned: the Lafayette Monument, Brooklyn, N.Y.; the Lincoln Monument, Lincoln, Neb.; the Longfellow Monument, Cambridge, Mass.; the Republic Monument and the Centennial Monument, Chicago, 111.; the President Harrison Monument, Indianapolis, Ind.; the Civil War Memorial and World War Memorial, Yale University; and the Parnell Monument, Dublin, Ireland. In 1920 the Lincoln Memorial, at Washington, D.C., designed by him, was completed, costing more than $2,500,000.

BACON, ROBERT (1860-1919), American banker, was born in Boston, Mass., July 5 1860. He graduated from Harvard in 1880 (in the class with Theodore Roosevelt), and the following year entered the banking house of Lee, Hig- ginson & Co., in Boston. In 1883 he became a member of the firm of E. Rollins Morse & Bro., and in 1894 joined the house of J. P. Morgan & Co., in New York. After conspicuous success in the financial world he resigned in 1903. He was Assistant Secretary of State, 1905-9, and then for a short time was Secretary of State, succeeding Elihu Root on the latter's election to the Senate. He was ambassador to France from 1909 to 1912. He attended the first Plattsburg Camp and was commissioned major in the U.S. Reserves in 1917, being assigned to the staff of Gen. Pershing with the A.E.F. in France. He returned to America with the rank of colonel, in 1918, and died in New York City, May 29 1919.

BACTERIOLOGY (see 3.156). Since bacteriology is so comparatively young a science, dating, as it does, from the introduction by Koch in 1880 of methods of technique which have made it an exact science, it is not surprising that the decade from 1911 to 1921 saw very considerable additions to our knowl- edge of the life and functions of the microorganisms with which it is concerned. These additions to knowledge will be reviewed here under two headings: general and agricultural, and medical.

Variations in Bacteria. It is probable that nuclear fusion between male and female gametes is essential for the preserva- tion of the special characters of an organism, and that in absence of sex fusion a species will tend to break up into a number of different strains. So far no fusion, either sexual or otherwise, has been observed amongst the bacteria. The characters of bacteria are extraordinarily liable to change according to the conditions of cultivation. Variations in morphology, cultural characters, physiological behaviour, virulence and pathogenicity have constituted one of the most striking features of modern bacteriology. Innumerable instances of such variations have come to light; space will permit of the citation of only a few typical cases.

Bacillus coli in the peritoneal cavity in the case of ascites may take the form of a diplococcus; in milk or in urine it may develop into a dense network of branching filaments resembling B. anthracis. Again B. carotovorus, an organism causing disease in many vegeta- bles, when present in the plant tissue appears as a very small rod; cultivated on artificial media the rods are much larger; in broth it grows in the form of long branching filaments, and in broth contain- ing sublethal doses of antiseptics, e.g. phenol and alcohol, it de- velops as a minute coccus.

It has recently been shown in separate communications that cer- tain organisms, B. lepisepticum and B. dysenteriae, when cultivated on artificial media, segregate each into two distinct types, one form- ing round colonies, the other diffuse and spreading ones; these types show variations also in agglutinability and in virulence, though otherwise their specific characters are identical. Once separated, the spreading forms in both cases remain true to type, and the question arises whether both strains coexist in the materials taken from the infected animals or whether the spreading forms appear as mutants shortly after removal from the natural habitat. This question can only be answered by investigations of cultures derived from single cells: the finding of segregation of mutants in cultures of this type would be of the greatest interest, but at present such investigations have not been conducted.

The sugar-fermentation reactions upon which much reliance is based in the diagnosis of species are unfortunately very susceptible to change under different cultural conditions; organisms can be " trained " to acquire fermenting powers which they do not normally possess. Strains of Bacillus carotovorus isolated from diseased plants grown in different localities were found to possess many various sugar- fermenting powers, but when cultured simultaneously through sev- eral transfers under the same conditions and again tested, all gave identical reactions.

All pathogenic organisms rapidly lose the property of virulence when cultivated apart from their hosts, and once lost it is very diffi- cult to restore this character. Virulence is altered rapidly by a change of environment; the attenuation of the anthrax bacillus by cultiva- tion at 40 F. instead of at blood temperature is a well-known phenomenon. Similar rapid reduction in virulence is attained by cultivation of organisms in presence of antiseptics.

One and the same species of an organism may give rise to different symptoms of disease in different individuals. The pathogenicity of Bacillus anthracis is considerably altered by exposure to the ultra- violet rays; the symptoms produced on inoculation of the altered strain into an animal are quite unlike the normal symptoms of anthrax. The change which the organism undergoes in the treat- ment with the ultra-violet rays persists after daily subculture for upwards of two months.

Transmutation in Bacteria. Many experiments have been described wherein bacteria became so changed in character as to suggest that they had undergone transmutation. One must not forget, however, that usually in dealing with cultures of bacteria one has a mixed population, the progeny of several individuals. Even though the culture may be made from a single colony on a plate it is more than probable that such a colony has arisen from a number of organisms herded together. The method of culture of such a population will tend to favour one strain and depress others, so that this strain may eventually be separated and appear as a mutant.

One piece of work, however, which requires confirmation before it can be accepted, should be cited in this connexion. It has been stated in a preliminary communication that Azotobacter may give rise to practically every form of organism to be found in the soil. The large round form of Azotobacter is said to pass in old cultures into a plasmodial stage from which it may emerge in the various