All these muscles are, like those of the fibrous coat, unstriped ; their elements consist of elongated shortish fibres, each possessing a long nucleus. (Fig. 523. a, Fig. 524.) In the thicker partitions there are what I call " cular fibre-cells," either stiff, pale, flat, from 4 to 6.1000ths of a line broad, and 2 to 3.100ths long, or more cylindrical, darker, shaped, and undulating, varying from 2 to 5.100ths of a line in length, and 3 to 4.1000ths in breadth. In both cases they have long, neat, small, staff-shaped, nuclei. In the finer partitions, on the contrary, appear many shorter and more spindle.shaped fibre-cells ; their nuclei are elliptical or even spherical, and they often project laterally from the fibres, so as sometimes to render these muscular elements scarcely distinguishable from the shaped epithelial cells of the splenic arteries. Themuscular elements just described are seen in the best and plainest manner in the pig and dog ; but they are also readily verified in the horse, ox, ass, sheep, and cat, in all of which they may frequently be isolated. In the other mammals previously, named, and in the rest of the vertebrata, they are less easily nised, and are scarcely susceptible of tion ; but they can ways be partially covered, and in any case may be strated by the tion of acetic acid, which displays their characteristic nuclei. As regards the man subject, I find that in the partitions which are visible by the naked eye, no trace of striped muscular fibre is present ; and they probably consist entirely of yellow and white fibrous tissue. In the finer partitions, on the contrary, elements occur to which one may perchance ascribe a muscular character. They are the same short fibres of a peculiar kind (fig. 525. 1.), which Ginsburg* has erroneously regarded as epithelial cells of the splenic veins ; otherwise they have hither to remained altogether unnoticed. They are characterised by their roundish or elongated oval nuclens, which is laterally disposed, and often occupies a pedunculated process ; by their homogeneous texture ; by their easy undulatory or serpentine outline ; and, finally, by their size, which offers a breadth of 15 to 25-1000ths, and a length of 2 to 3-100ths of a line. The round nuclei of these fibre-cells, even at first sight, somewhat militate against their muscular import ; but it must be recol lected, that in the mammals narned it has been previously stated that the muscular fibre-cells, which occur in the smallest partitions, deviate considerably from the characteristic fibres, and greatly resemble the structures now de scribed in men. On this account, and from 'the further fact, that the above mentioned human fibre-cells, in moderately fresh spleens, seem to occupy the smallest partitions, just as the muscular fibres in animals ; while in later periods after death, or in decomposed spleens, they can only be found isolated, with the pa renchyma cells, in the red pulp of the spleen, I formerly considered it not too hazardous to regard them as muscular fibre.cells. But more recently I have made some observations which have again thrown me into complete uncer tainty in respect of the import of these ques tionable structures. Thus I believe myself to have verified, that these fibres occur in the human subject rolled together in a kind of spherical cell (fig. 525. 2,) of 5 to 7-1000ths of a line in diameter ; and that, on tearing up this structure they become free, and extend themselves. But, since this fact in no way harmonizes with the nature of muscular fibre cells, and is besides altogether obscure and incomprehensible to me, I hesitate to express at once an opinion concerning the above mentioned structures in the human spleen, but 'am desirous of calling the attention of inquirers to this peculiar arrangement, which, on ac count of its constancy and frequency, is very interesting.
4. The splenic corpuscles or Ilialpighian cor puscles °fine spleen (vesiculce seuglandulcelienis, s. corpuscula Malpighii) are whitish spherical corpuscles, which are imbedded in the red spleen substance of certain animals, and are connected with the smallest arteries. In the dead bodies of men, in the state in which they are generally subjected to examination in hos pitals, these corpuscles are very seldom seen. On this account, some of the earlier observers, as Rudolphi, Heusinger, Andral, and others, and more recently Gluge * and Oesterlen have regarded them as not constant structures, or even as products of disease; or have considered them as J. Muller formerly did
to be altogether distinct from the splenic cor puscles of the Ruminantia. But this view is erroneous, and since Giesker §, Krause II, and Bischofflf, who described the splenic cor puscles of the human subject, and showed their correspondence with those of the mam malia ; and since the revocation by Miiller of his earlier opinion**, all observers are tolerably agreed, that although the corpuscles in question are often deficient in the human subject, yet they are not the less to be re garded as normal structures, which are in variably present in the healthy subject.
The frequent deficiency of the splenic corpuscles is explained by many circum stances. Most of the observations of them concern human individuals, in whom a long abstinence from food has preceded death. In such cases, as Henle has well remarked 1-1-, the apparent absence of the corpuscles is easily explicable, since their size is notoriously regulated by the quantity of ingesta. So, also, great number of the human spleens which come under our notice are diseased; either softened, distended with blood, and soaked through with extravasations, or enlarged, hardened, atro phied, or already half decomposed and putrified. Finally, the human spleen corpuscles are very delicate, and easily destroyed. As to the fre quency of their occurrence in diseased sub jects, we are supplied with accurate data by v. Hessling, who has given the results of 960 dissections. Of the whole number just men tioned, Malpighian corpuscles were only pre sent in 116, or in about every eighth indi vidual. He also adds the following numerical stateinent respecting the different ages of life. In the first and second year of life the cor puscles were present in every second subject ; from the second to the tenth year, in every third subject ; from the tenth to the fortieth year, in every sixteenth ; from the fortieth year to old age, in every thirty-second. These numbers are in general correct, and are readily explicable when we recollect that diseases of the spleen are more numerous as age ad vances. But the results of my own observa tions coincide with those of Oesterlen, in representing the number of cases in which corpuscles are detected as .greater than that above mentioned. This difference may be ascribed to the difficulties which often prevent the recognition of the dwindled spleen cor puscles; thus in many cases where the first view has afforded no signs of their presence, the application of soda, or the washing of the pulp, has brought them into view.
On the other hand, it is absolutely certain that, in many spleens, they disappear without leaving any traces, and cannot be made visible by any method of treatment. In the bodies of healthy individuals which are examined while fresh, they may always be detected ; at least, there are very numerous observations extant in which they have been found after accidental deaths, executions, suicides, Sze. ; and to these cases I myself am enabled to add two. So, also, I have found them in a great majority of the bodies of children which I have examined ; and here they are both very distinct and numerous, so as not to offer any visible difference, in these respects, from those of the Ruminantia.
The size of the Malpighian corpuscles ex periences many variations both in men and animals, even apart from the effects of dis ease : they measure from one-tenth to one third of a line; on an average, about one-sixth. Their size has hitherto been sotnewhat too highly estimated ; and chiefly on this account, that sufficient preliminary care has not been taken to isolate them from the surrounding parts : when this is done it will be found, that they are not so large as appears from viewing them on a section of the spleen ; and that, in many cases, they measure less than the given bulk. The fluctuations in their size depend not merely upon tbe differences of individuals, but obtain in one and the same animal : in this latter case, they appear mainly to be regulated by the condition of the chylopoietic viscera ; although accurate data, as to these points in the human subject, are altogether deficient.