INVERSION. 728 INVESTITUBE. By inversion, major intervals become minor, anil' minor become major; diminished intervals become augmented, and augmented become di- minished. But the two perfect intervals of the fourth and the fifth remain iii-rfc.t « lii'U in- verted. In the^e examples the lran>|iii><il nolc is placed an octave liifjlier. but naturally the same result is arrived at by transposing it down- ward, as will be seen by reading the table back ward. For inversion of chords. se<- Ciiohd. Kor inversion of phrases or passages, see CofSTF.R- roiNT. INVERSION (in mathematics). Sec Circle. INVERT'ASE (from invert)- One of the enzymes ((|.v.) which aet.s upon certain sugars, especially upon cane-sugar ( saccharose i . which it hydrolyzes, forming grape-sugar (glucose) and fruit-sugar (fructose). Inverta>e a<ls most rapi<Ily at .50° to 00° C, in a slightly acid me- dium. It can break up practically unlimited quantities of the sugar without being it-elf ma- terially diminished. Invertase occurs in many fungi and in some bactc-ria : more recently it has been found widely distributed in the seed- plants, in whose nutritive work it plays an important part, because cane-sugar is probably one of the most widely distrilnitcc] foods in the higher plants. Invertase is wcreted al)undantly by yeast, and without it yeast is unable to fer- ment cane-sugar, .ftcr inversion of cane sugar the i)roduets are broken up by the enzyme zymase (i|,v.), See I'"t-:RMKNTATloN. INVERTEBRA'TA ( Xeo-Lat. nom. pi., from T,at. 1)1-. not + II rlihrahin. vertebrate, from vrrlrbra. joint, from vcrlerr. Skt v<irl. OC'hurch Slav, vruifli, to turn, Goth. itnir]<an. .S. icror- pan, ()H(i. werdaii, Ger. ircrdrii. to become). Ani- mals which do not have a vertebral column or spine. The term is used in contrast with Ver- tebrate (q.v.). or animals with a backbone. One group, then, is formed on positive and the other on negative characters, liiforc the anatom- ical stnicttire and the embryologiial develop- ment of animals was very generally worked out. the barrier between invertebrates and verte- brates was supposed to lie absolute: but with the refinement of anatomical and embrvological methods of study, brought about in a great measure by the use of the microscope, the hiatus between them is nearly bridged over, .scidians are now considered to be degenerate ancestors of vertebrates: some of the nemertean and eha-topod worms approach vertebrates in certain characters, and Balanoglossus and fcphalodiscus (q.v.) arc frequently called hemi-chordata (see .•DEi.oriiORnA) , because they are so near the botindary line between vertebrates and inver- tebrates that they can be said to he only half- vertebrates. .And not only has this barrier been broken down. hut. with our increased knowledge, the absolute independence and isolation of many different groups of invertebrate animals which the earlier systematists lielieved to exist must be abandoned. The foundation of the zoiilogy of these animals as there defined, was laid by Lamarck (q.v.) in a monumental work. Sr/.s/('»ic drs animnux snnD vertrhrri. published in Paris in 1801; followed in 181.5-22 by his Histoire no- turrllr tin: animnux .inns lertihrcn. INVEST^TTIRE (Lat. investitura, from in- vestirr. til invest, from iii. in + rcitire. to clothe, from lestifi, garment: connected with Gk. fyyii/at. hennynai, Skt. vas, Goth, icasjan, OHO., AS. icirioii, Eng. iccar). In feudal and ecclesiastical history, the act of giving corporal possession of a manor, olbce, or beneliee, accompanied by a cer- tain ceremonial, such as the delivery of a branch, a b:inncr, or an instrument of (jllice, more or less designed to signify the power or authority which it was supposed to convey. The chief interest is in ei'clesiastical investitures, and the contest which arose concerning them is so interwoven with the whole course of mediaeval history that a brief account of its nature and origin is indispen- sable to a right understanding of many of the most important evunts of that period. The sys- tem of feudal tenure had bccume so universal that it affected even the land held by ecclesiastics, and attached to most of the higher ecclesiastical dignities, monastic as well as .secular. Accord- ingly, ecclesiastics who, in virttie of the ecclesi- astical othec which they held, came into posses- sion of the lands attached to such offices, were regarded as becoming by the very fact feudatory to the suzerain of these lands; and. as a not nn- iialural result, the suzerains thought themselves entitled to claim, in reference to these personages, the same rights which they enjoyed over the other feudatories of their domains, .mong these rights was that of granting solenm investiture. In the case of bishops, abbots, and other Ghiirch digni- taries, the form of investiture consisted in the delivery of a pastoral staff or crosier, and the placing of a ring tipon the finger; and as these badges of office were emblcmatit — the one of spir- itual care if souls, the other of the espousals, a* it were, between the pastor and his church or H'onastcry — the possession of this right by the lay princes, which they had held since the time of Charles the fiicat. became in the latter ])art of the eleventh century a source of disquietude to the Church. On the part of the suzerains it WHS maintained that they did not claim Ui grant by this rite the spiritual powers of the office, their functions being solely to grant possession of its temporalities, and of the rank thereto an- nexed. But the Church party urged that the ceremonial involved the granting of spiritual powers; insomuch that, in order to prevent the clergj' from electing to a see when vacant, it was the practice of the emperors to take jiossession of the crosier and ring, until it should be their own pleasure to grant investiture to their favorites. The investiture strife was complicated by the rebellions of the nobles in Germany: by thi- strife W'tween rival parties in the Lombard cities: by the conllict of parties in Rome; and siiceifically hv the question of the property of Countess Ma- tilda of Tuscany. (See ^tATII-l)A ; Gf.hmaxv; TIexry IV.) The disfavor in which the practice of investiture was held by the clergy- ftaind its most energetic expression in the person of Greg- ory VIL. who. having, in the year 1074. enacted most stringent measures for the repression of simony, proceeded, in 1075. to condemn, under excommunication, the practice of lay investitures, as almost necessarily connected with simony, or leading to it. This prohibition, however, only regarded investiture in the ohjectionable form in which it was then practiced, or investiture of whatever form, when the ofTiee had been ob- tained simoniacally. But other members of the clergy went much further, ami a pope of the same century. Urban II. (lOOo). absolutely and entirelv forbade, not alone lay investiture, but
