Volume 1

Elements of physiology : for the use of students, and with especial reference to the wants of practitioners / Tr. from the German, with additions by Robert Willis.

  • Wagner, Rudolph, 1805-1864.
Date:
1841-2
Catalogue details

Licence: Public Domain Mark

Credit: Elements of physiology : for the use of students, and with especial reference to the wants of practitioners / Tr. from the German, with additions by Robert Willis. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    22/244 (page 12)
    Among Birds two principal varieties are observed in the form of the spermatozoa: they have either a long slender body, perfectly cylindrical as it seems, with a tail extremely thin, fiUform, and ai'ising at once, not tapering off from the body, and once or twice as long again as this part; this appears to be the type in the Rapaces, Scansores, pallinse, Grallas, and Palmipedes; or the cylindrical body is poij/ited anteriorly, and then makes several, generally from three to four, spiral turns, so that it resembles a corkscrew, and then tapers off gradually into a long straight tail, that grows smaller as it approaches its end. This is the type in the Passeres (fig. IV. a, c, d,f, g). The number of spiral turns, and the angle at wdiich they proceed, are different in the different families and genera. The tail is of very dissimilar length and thickness. If the spiral be much drawn out and more sinuous in its appearance, the turns pass into each other under blunter angles, as in the Thrushes for example (fig. IV./.) ; in the Shrikes (Laniadae), again, the spiral is greatly contracted, and the turns appear almost acutely angular [g]; the tail is here short and delicate, so that the whole animalcule measures but from the fiftieth to the sixtieth of a line in length; whilst in the Finches (Fringillidaj) they are much larger and stronger; in the Chaffinch, for instance (Fringilla coelebs, fig. IV. a), they are the sixth of a line in length, the tail is very strong and rigid, and here, as among the Passeres generally, is never observed to move in the motions of the animalcule. In the scaly families of the Amphibia, the lizards and serpents, the spermatozoa have for the most part an elongated body, and a delicate, filiform tail, like those of birds in general [e. g. the common dimensions of die body of the spermatozoa; but this depends in part, at least, on the degree of dilution of the semen, on its freshness, on the degree of hveliness or power of motion, &c. &c. exhibited by these animalcules. The descriptions here given, and the forms presented, are all from spermatozoa in the most recent state possible. In beginning the study of the spermatozoa without assistance, I would particularly recommend the rodent tribes as the proper subjects, by reason of the magnitude and the decisive forms peculiar to their seminal animalcules. Let any one, for example, cumpare the seminal fluid of the mouse and rat, and he will immediately find that the spermatozoa of these two so closely allied animals present typical similarities not to be mistaken in the important matters of size, form of body, &c. &c. at the same time that they still exhibit specific differences adequate to distinguish them in every case from one another, and when they are contra-ted. Other rodent ani- mals, the srpiirrel, to cite a single case? have very peculiar and large spermatozoa, the margins of the body being turned up in some sort like the brim of a hat, &c. &c. Large animals, the horse, the ox, &c. have smaller and less specifically and obviously diversified spermatozoa, so that it is not so well to begin with these animals in analyzing the seminal fluid.