SPLEEN. 



795 



loops or with free extremities. In the calf, 

 the thickness of these smallest nerves on 

 arteries of a line in diameter (where it is 

 not uncommon to find two such trunks) is 

 24 to 28-1000ths of a line ; on the pencils of 

 arteries 48 to 56-10,OOOths ; on the smallest ar- 

 teries and capillaries 3 to 4-1000ths. Their 

 structure was so far peculiar, that in the calf 

 the finest nerves (Jig- 539.) exhibited no trace 

 of nerve fibres, even when treated with soda 

 and acetic acid, but they seemed to consist 

 wholly and solely of the fibres of Ilemak. 

 Nevertheless, in branches of 12 to '28-1000ths 

 of a line, I have often very plainly seen a single 



Fig. 540. 



A somewhat larger nerve, in which may be seen, a 

 sin file dark nerve fibre : also from the Calf. Mag- 

 nified 350 diameters. 



nerve tubule of 20 to 28-10,OOOths of a line 

 (Jig. 540.), with dark margins, in the midst of 

 the fibres of Remak. From these facts it may 

 be concluded that the finest nerve tubes in the 

 spleen of the calf are devoid of the dark bor- 

 ders, just as they are in the organ of smell 

 according to TodJ and Bowman ; or as in the 

 Pacinian corpuscles, the cornea, &c. ; but we 

 are scarcely able to conclude therefrom that 

 they possess the same constitution in the 

 adult animal. I will here permit myself to 



Fig. 541. 



Two primitive nerve fibres given off from the trnnli of 

 vc of the Calf, about an inc/i before its 



the splenic nerve < 

 entry into the Spleen. 



Magnified JuO diameters. 



add an interesting microscopic observation 

 concerning the splenic nerves of the calf. A 

 division of the primitive nerve fibres takes 

 place in them (fig. 541.), similar to that which 

 Henle and myself found in the Pacinian cor- 

 puscles, M tiller, Briicke, and R. Wagner in 

 the muscles, and Savi and R. Wagner in the 

 electrical organ of the torpedo. But what is 

 altogether new in the minute anatomy of nerve 

 is, that these divisions do not take place at 

 the terminations of the primitive nerve fibres, 

 but in their trunks. I detected them in the 

 large trunks which accompany the splenic 

 artery previously to its entering the hilus ; 

 and, indeed, in considerable numbers, so that 

 I often counted three or four such divisions 

 in one preparation. They always took place 

 by the division of a primitive nerve fibre at an 

 acute angle into two parts, and never gave 

 rise to more fibres. These divisions often 

 repeated themselves on the same fibre, so 

 that in one instance three, and in another 

 case even four, fibres were given off by the 

 successive divisions of a single primitive fibre: 

 this happened in the smaller branches in the 

 interior ; but, so far as I could remark, it did 

 not occur in the smallest branches of nerves, 

 although, from the difficulty of examining the 

 finer nerves, I cannot say that such divisions 

 were absolutely wanting here. The significa- 

 tion of these facts seems to be very important, 

 botli in an anatomical and physiological point 

 of view, but this is not the place to give a 

 more detailed statement. But thus much 

 will I remark ; that by means of such a dis- 

 tribution of the nerves, a small nerve may be 

 rendered subservient to a larger organ ; and, 

 in addition, an harmonious activity of the 

 whole organ may be facilitated ; while, finally, 

 in respect to sensation, it may possibly ex- 

 plain the want of an exact local sensibility. 



In concluding this treatise on the anatomy 

 of the spleen, I will allow myself briefly to 

 propound somewhat concerning the physio- 

 logical and pathological 'properties of the 

 organ. 



The spleen is developed at the end of the 

 second or the beginning of the third month, 

 in the fcetal mesogastrium at the fundus of the 

 stomach. It originates from a blastema which 

 is developed independently in this situation, 

 and neither proceeds from the intestine, like 

 that of the liver, nor from the pancreas, as 

 Arnold has maintained ; since, although in 

 the ruminants it is placed on this gland, yet 

 in the dog, according to Bischoff, it is not. 

 It is at first a small, white, often slightly lo- 

 bulatcd corpuscle, which gradually reddens, 

 and soon becomes as rich in vessels and 

 blood as it is in the adult. The elements of 

 the fcetal spleen are originally quite uniform 

 cells ; at a later period part of these are 

 transformed into fibres and vessels, while part 

 become persistent as the parenchyma-cells. 

 It is only subsequently that the Malpighian 

 corpuscles are developed, yet I have found 

 them, without exception, both in man and 

 animals, at the end of the fetal life. Ac- 

 cording to Heusinger, the proportion of the 



