412 L E E L E G
origin and propagation of "this minute and despised creature," which some asserted to be produced from sand, others from dust, others from the dung of pigeons, and others from urine, but which he showed to be "endowed with as great perfection in its kind as any large animal," and proved to breed in the regular way of winged insects. He even noted the fact that the pupa of the flea is sometimes attacked and fed upon by a mite, – an observation which suggested the well-known lines of Swift.
Although Bonnet is usually credited with the discovery of the viviparous propagation of the Aphides, this had been really made by Leeuwenhoek half a century previously. For, his attention having been drawn to the blighting of the young shoots of fruit- trees, which was commonly attributed to the ants found upon them, he was the first to find the Aphides that really do the mischief; and, upon searching, after his wont, into the history of their genera- tion, he observed the young within the bodies of their parents. He carefully studied also the history of the ant, and was the first to show that what had been commonly reputed to be "ants' eggs" are really their pupæ, containing the perfect insect nearly ready for emersion, whilst the true eggs are far smaller, and give origin to "maggots" or larvæ.
Of the sea-mussel, again, and other shell-fish, he argued (in reply to a then recent defence of Aristotle's doctrine by Bonami, a learned Jesuit of Italy) that they are not generated out of the mud or sand which is found on the sea-shore or the beds of rivers at low water, but from spawn, by the regular course of generation. For my part," he says, "I hold it equally impossible for a small shell-fish to be produced without generation as for a whale to have its origin in the mud."[1] And he maintained the same to be true of the fresh-water mussel (Unio), whose ova he examined so carefully that he saw in them the rotation of the embryo, a phenomenon supposed to have been first discovered long afterwards. "This uncommonly pleasing spectacle," he says, "was enjoyed by myself, my daughter, and the engraver for three whole hours, and we thought it one of the most delightful that could be exhibited." Not only was he the first discoverer of the rotifers, but he showed "how wonderfully nature has provided for the preservation of their species," by their tolerance of the drying-up of the water they inhabit, and the resistance afforded to the evaporation of the fluids of their bodies by the impermeability of the casing in which they then become enclosed. "We can now easily conceive," he says, "that in all rain-water which is collected from gutters in cisterns, and in all waters exposed to the air, animalcules may be found; for they may be carried thither by the particles of dust blown about by the winds." Although Baker is usually credited with the first careful study of the "wheel-animalcule," yet he really added very little to the account long previously given of it by Leeuwenhoek. In the same spirit he investigated the generation of eels, which were at that time supposed, not only by the ignorant vulgar, but by "respectable and learned men," to be produced from dew (!) without the ordinary process of generation. He was rewarded by the discovery of their viviparous propagation, – his careful and prolonged observations on which point, though since called in question, have never been refuted. The spectacle of the minute eels lying together in a transparent liquid within the body of the female gave him, he says, great pleasure, – affording a complete answer to those who said behind his back, "Since Mr Leeuwenhoek is endeavouring to establish the regular generation of all animals, let him show us in what manner eels are bred."
Altogether it does not seem too much to affirm that Leeuwenhoek is well entitled to be considered, not only as the father of scientific microscopy," but as having contributed more than any other naturalist to the overthrow of the doctrine of "spontaneous generation," and as having set a most admirable example of scientific method in the prosecution of biological research.
Leeuwenhoek's contributions to the Philosophical Transactions amounted to one hundred and twelve. He also published twenty-six papers in the Memoirs of the Paris Academy of Sciences. Two collections of his works appeared during his life, one in Dutch, and the other in Latin, – the most complete edition having been published at Leyden shortly before his death in 4 vols. (1719-22). A selection from this, translated into English by S. Hoole, was published in London (1798-81), 2 vols. 4to. (W. B. C.)
LEEWARD ISLANDS. See West Indies.
LEFÈVRE D'ÉTAPLES. See Faber, Jacobus.
LEGATE, one of the special names of a messenger or ambassador of the pope. The first four centuries present us with no actual recorded instances of recognized delegation of the papal authority; for that Hosius acted as papal legate at the council of Nice is nothing more than an assertion of Gelasius of Cyzicus, who wrote about the end of the 5th century, and no Western prelate took any part, either personally or otherwise, in the first council of Constantinople. The fifth (sometimes called the seventh) canon of the council of Sardica, in 343, however, shows that the possibility of such delegation had already begun to be discussed, and suggests that it may actually have been exemplified before that date. This canon provides that, in case of an appeal by a deposed bishop to Rome, if the pope is inclined to grant a new trial, it shall be competent for him to write to the bishops of the neighbouring province, but if the appellant wishes the pope to send priests from his own side ("ut de latere suo presbyteros mittat"), it shall be free to the pope to do so, and give them due rank and dignity in the court thus constituted (Hefele, Conc., i. 568). Instances of delegation of the papal authority in various degrees become numerous in the course of the 5th century, especially during the pontificate of Leo I. Thus Leo writes in 444 (Ep. 6) to Anastasius of Thessalonica, appointing him his vicar for the province of Illyria; the same arrangement, he informs us, had been made by Pope Siricius in favour of Anysius, the predecessor of Anastasius. Similar vicarial or legatine powers had been conferred in 418 by Zosimus upon Patroclus, bishop of Aries. In 449 Leo was represented at the "Robber Synod," from which his legates hardly escaped with life; at Chalcedon, in 451, they were treated with singular honour. Again, in 453 the same pope writes to the empress Pulcheria, naming Julianus of Cos as his representative in the defence of the interests of orthodoxy and ecclesiastical discipline at Constantinople (Ep. 112); the instructions to Julianus are given in Ep. 113 ("hanc specialem curam vice mea functus assumas"). The designation of Anastasius as vicar apostolic over Illyria may be said to mark the beginning of the custom of conferring, ex officio, the title of legatus upon the holders of important sees, who ultimately came to be known as legati nati, with the rank of primate; the appointment of Julianus at Constantinople gradually developed into the long permanent office of apocrisiarius or responsalis. Another sort of delegation is exemplified in Leo's letter to the African bishops (Ep. 12), in which he sends Potentius, with instructions to inquire in his name, and to report (vicem curæ nostræ fratri et consacerdoti nostro Potentio delegantes qui de episcopis, quorum culpabilis ferebatur electio, quid veritas haberet inquireret, nobisque omnia fideliter indicaret). Passing on to the time of Gregory the Great, we find Augustine of Canterbury sometimes spoken of as legate, but it does not appear that in his case this title was used in any strictly technical sense, although the archbishop of Canterbury afterwards attained the permanent dignity of a legatus natus. Boniface, the apostle of Germany, was in like manner constituted, according to Hincmar (Ep. 30), a legate of the apostolic see by Popes Gregory II. and Gregory III. According to Hefele (Conc., iv. 239), Rodoald of Porto and Zecharias of Anagni, who were sent by Pope Nicolas to Constantinople in 860, were the first who are actually called legati a latere. The policy of Gregory VII. naturally led to a great development of the legatine as distinguished from the ordinary episcopal function. According to the Nova Compilatio Decretalium of Gregory IX., under the title "De officio legati" the canon law recognizes two sorts of legate, the legatus natus and the legatus datus or missus. The legatus datus (missus) may be either (1) delegatus, or (2) nuncius apostolicus, or (3) legatus a latere (lateralis, collateralis). The rights of the legatus natus, which included concurrent jurisdiction with that of all the bishops within his province, have been much curtailed since the 16th century; they were altogether suspended in presence of the higher claims of a legatus a
- ↑ Leeuwenhoek's argument in this instance was partly based on false premises. For he imagined the Lepraliæ with which mussel-shells are often encrusted to be the eggs of the mussels, and the contained Polyzoa, whose sixteen tentacles he figures, to be the young mussels.
