EXCHEQUER 72 EXCRETION other currencies intervening between the two. In arithmetic, a rule for ascertain- ing how much of the money of one coun- try is equivalent in value to a given amount of that of another. In law, a mutual grant of equal interests, in con- sideration the one for the other. Theory of exchange, a hypothesis with regard to radiant heat, devised by Pre- vost of Geneva, and since generally ac- cepted. All bodies radiate heat. If two of different temperatures be placed near each other, each will radiate heat to the other, but the one higher in temperature will receive less than it emits. Finally, both will be of the same temperature, each receiving from the other precisely as much heat as it sends it in return. This scale is called the mobile equilibrium of temperature. EXCHEQUER, in Great Britain, the department which deals with the moneys received and paid on behalf of the public services of the country. The public rev- enues are paid into the Bank of England (or of Ireland) to account of the ex- chequer, and these receipts as well as the necessary payments for the public service are under the supervision of an important official called the controller and auditor-general, the payments being granted by him on receipt of the proper orders proceeding through the treasury. The public accounts are also audited in his department. EXCOMMUNICATIOlsr, a word de- noting exclusion, whether temporary or permanent, from fellowship in religious rites, involving also, where participation in such rites is required in the civil order, privation of the rights of citizenship. It is not peculiar to the Biblical religions, but is found in most of the sytematized cults, whatever their origin. The clear- est analogy, however, to the Christian discipline of excommunication is that furnished by the Rabbinical code. The offender first received a public admoni- tion, and seven days later, if he did not make satisfaction, the lesser excommuni- cation, Niddui, was pronounced against him, whereby he was isolated during 30 days from contact with all save his wife and children, being obliged to keep at least four cubits' distance from all others; and though the sentence did not technically include expulsion from the synagogue, yet this provision practically enforced it. At the expiration of 30 days, a second term of like duration was en- joined in case of continued impenitence; and the contumacious were then visited with the greater excommunication of Cherem, which excluded both from the synagogue and from all social intercourse, and the offender was treated as a leper. These two grades of excommunication were the only ones anciently in use; but the later rabbins added a third and se- verer one, styled Shammatha or Anathe- ma Maranatha, which was lifelong, at- tended with solemn imprecations, and sometimes entailing forfeiture of goods. The Christian system of excommuni- cation is based doctrinally on the precept of Christ (Matt, xviii: 15-18) and on the precepts and practice of St. Paul. It was primarily, as the word denotes, ex- clusion from communion in the eucharist and the agape, or love-feast, including also suspension from office in the case of clerical offenders; and it was distin- guished as major and minor, each having various degrees of severity. The most notable exercise of the power of excommunication in the modern Angli- can Church was when Bishop Gray, as Metropolitan of Cape Town, deprived and excommunicated Bishop Colenso of Natal in 1863, which sentence, approved by the Convocations of Canterbury and York, the General Convention of the American Episcopal Church, the Epis- copal Synod of Scotland, and the Pro- vincial Council of Canada, was reversed by the Judicial Committee of Privy- Council in 1865. In the Established and other Presby- terian Churches of Scotland, the lesser excommunication, involving deprivation of all "sealing ordinances," can be pro- nounced by the kirk session. Islam forms an exception to the almost universal incidence of the practice of excommunication. Under the Moslem code every religious offense carries with it a temporal penalty, such as fines, scourging, stoning, or other mode of death, and only in this last manner can an offender be cut off from the congrega- tion. EXCRETION, the process in animal and plant physiology which separates from the essential substance or animal body waste matter of no further use in nutrition. The organs so employed par- take of the characters of strainers, which retain substances soluble in the blood necessary to health and extrude the harmful. The primary excretory organs in vertebrates are the kidneys. The function of these is to separate from the blood the waste materials pro- duced by the decomposition of nitrog- enous substances and expel them from the body. The lungs and the skin likewise perform some of the duties of excretory organs. In its simplest form the excre- tory organ is found in the Protozoa, in which the contractile vacuole by means