Esters

ESTERS, complex ethers, organic compounds characterized by the presence of an oxygen atom which links an alcohol radical to an acid radical: R-CO-O-R' (R is the alcohol residue).

In contrast to simple ethers, which contain an oxygen atom linking two alcohol radicals: R1-O-R2. Orthoesters are esters which result from the substitution of hydrogen atoms of the hydroxyl groups of hypothetical trihydrates of monobasic organic acids by alcohol residues. Such esters, of the structure R-C(OR')3, are known only for formic and acetic acids. Orthoesters of carbonic acid have the structure C(OR')4. Esters are very widespread in the plant and animal worlds: fats (see), wax (see), spermaceti (see), lecithin (see), etheric acids (see); many fragrant substances found in essential oils, intermediate substances of carbohydrate metabolism [for example, hexosephosphoric acids (see)] and a whole series of other substances belong to the class of esters. Esters are in most cases liquids or solids, often with a specific odor, poorly or not at all soluble in water, but largely well soluble in alcohol and ether. Most esters distill without decomposition at normal or reduced pressure; this property of esters was brilliantly used by Emil Fischer in his method for separating the mixture of amino acids formed during the hydrolysis of proteins by their esterification and fractional distillation in a vacuum. Esters easily decompose under the influence of alkalis into alcohol and acid—the saponification reaction, the reverse of the esterification reaction. Under biological conditions this decomposition proceeds under the action of enzymes—esterases (or lipases). The saponification reaction is a typical reversible reaction; it does not go to completion, and the equilibrium position can be reached by synthesis under the action of the same catalysts, including enzymes, also from the side of the decomposition products—alcohol and acid. Many esters find application in medicine as pharmaceutical preparations: aspirin, salol, phytin, ethyl nitrite, glycerol nitrates, cocaine, novocaine, atropine, etc. In industry, ethyl and amyl acetates, used for the manufacture of high-grade lacquers for the aviation industry, are of great importance. Many esters find application as artificial fruit essences. The production of esters, as well as their application, is often associated with the possibility of occupational poisoning due to their volatility.

A. Kuzin. ESTONIA. General data and population movement. Surface area 47,549 sq. km., population in 1933—1,128 thousand, population density per sq. km. in 1928—23.5 inhabitants. Mortality in 1933 was 14.8 per 1000, birth rate—17.6, natural increase—2.8; thus, Estonia after France has the lowest natural increase in Europe. Child mortality in Estonia is not high, but over the last 10 years it shows no tendency to decrease. In 1931, 102.8 out of 1000 births died. - Sanitary organization. The sanitary administration of Estonia is part of the Ministry of Labor and Social Welfare. At its head stands a doctor appointed directly by the government on the proposal of the Minister of Labor. The central sanitary administration includes two departments: general and pharmaceutical. The State Sanitary Council is attached to it, the chairman of which is the director of the Central Sanitary Administration and which includes the director of the University Hygiene Institute, the chief army doctor, the chairman of the Red Cross, representatives of local sanitary organizations, etc. The sanitary administration covers sanitary statistics, sanitary protection of borders, the fight against infectious and social diseases, alcoholism, supervision of private and state hospitals, medical practice, pharmacies, slaughterhouses, food products, school hygiene, labor hygiene, etc. Laws relating to public health are developed and proposed by the State Sanitary Council. In each district and city there is its own sanitary administration, headed by doctors proposed by the district self-government or by the assembly of city electors and approved by the chief sanitary director. In addition, in each county there is a county doctor, the functions of whom correspond to those of district doctors, but within the county. Local sanitary administration is charged with supervising the execution of sanitary legislation, local doctors and hospitals, the study of sanitary living conditions, registration of infectious diseases, providing medical aid to the destitute, etc. Local administration appoints doctors for city or rural public hospitals and schools, as well as doctors for medical aid to the destitute. By the law of December 16, 1927, the entire health care system was precisely codified. By the law of November 10 of the same year, psychiatric hospitals passed to the state. The mentally ill, epileptics, the feeble-minded, disabled children, the blind and the deaf-mute have the right to state support and treatment if their parents do not have the means to support them. Infectious and social diseases. The situation has changed relatively little since the time when Estonia was part of the Tsarist Russia. Acute epidemics of typhus and smallpox, which flared up at the end of the imperialist war, gradually subsided, and the incidence of infectious diseases now remains at more or less a constant level. Thus, the incidence of infectious diseases fell from 142.1 per 10,000 inhabitants in 1920 to 45.3 in 1928 and has since stood almost at the same level. The incidence and mortality from tuberculosis are very high (the highest in Europe). In 1928, the incidence per 100,000 inhabitants was 1,336, mortality per 100,000—228.5, the number of deaths from tuberculosis (absolute figures)—2,515. - Venereal diseases are also widely spread. By the law of January 1, 1927, treatment of venereal diseases during the infectious period is mandatory and free. However, prostitution is permitted and regulated. The number of regulated prostitutes rose from 553 in 1924 to 807 in 1929 and has since grown even more. The number of suicides in the country is also growing—one of the highest in Europe (gradually rising from 11.7 per 100,000 inhabitants in 1922 to 30.2 in 1930). The number of mentally ill, which in 1902 was 7.9 per 1,000 inhabitants, fell in the post-war period to 3.1 due to the absence of registration. In 1927/28 it rose to 7.4. Cancer cases constitute 5.1 per 10,000 inhabitants in 1922 and 7.3 in 1928. - Medical care. The number of doctors in 1929 equaled 856 against 370 in 1921, of them in rural areas—224 (dentists—197). The number of midwives rose from 358 in 1927 to 416 in 1929 and fell to 370 in 1934. In 1929 there were 194 pharmacies (in 1925—178). According to 1928 data, there were 36 hospitals with 2,615 beds, of them 9 state (with 723 beds), 17 local public (1,506 beds), 10 private with 386 beds. There was also one leprosarium with 16 beds, 2 psychiatric hospitals with 730 beds and 3 sanatoriums with 136 beds. - Motherhood and childhood protection has a philanthropic character. The Ministry maintains 4 orphanages for abandoned children, almost exclusively illegitimate. It also subsidizes orphanages organized on local or public funds. Altogether in Estonia there are about 30 such orphanages with 1,500 children. There are 5 maternity clinics. Maternity protection by legislation is set very weakly. Pregnant workers have the right to leave before and after childbirth, but the leave is not paid. The number of abortions is high: in 1927 there were 2,756 abortions in the city (44.1 per 100 normal births); in rural areas—958 (7.1 per 100 normal births) (more recent data are not available). The percentage of stillbirths is very high, although it is decreasing in recent years (from 25.3 per 1,000 births in 1921 to 19.7 in 1928). - Social insurance. Compulsory insurance against accidents and diseases exists, but its scope applies only to industrial workers and their families. The sick person has the right only to medical service and to medicines. Medical service lies with the employer or with the insurance fund doctor; a contract is also possible between the employer or the insurance fund and a private practitioner. Health care budget. Data are available only for old years, as they are not published in the latest statistical reviews. Starting from 1926, the health care budget is being reduced. General health care expenses by the Ministry of Labor and Social Welfare in 1928-29 (from April 1 to April 1) amounted to 2,730,896 Estonian crowns (against a total state budget of 75,834,343 crowns), i.e., 3%. Lit.: Sanitary Yearbook of the League of Nations, Geneva, 1924-1930.

A. Ruakid.