Anatomy of the Umbilical Cord. 429 



their injection minus the extreme distention. I have never seen any 

 appearance of endothelia in these canals ; but there is a very constant 

 relation of nuclei to their walls in the lacunar spaces. These nuclei, 

 when examined by a power of 200 diameters, seem to be fusiform (Plate 11. 

 fig. 8) ; but when examined by a sixteenth immersion-lens, they are found 

 to be of a regular oval shape, and to have a nucleolus which is very small 

 in proportion to the mass of protoplasm (Plate 11. fig. 7). They are not 

 always solitary, and occasionally one large nucleus may be seen asso- 

 ciated with a number of smaller structures which seem identical. These 

 nuclei are readily shown by acetic acid ; but by such treatment their re- 

 lations to the lacuna? are destroyed. They readily take up the colouring- 

 matter of an indifferent solution of hsematoxylin ; but I have not yet been 

 able to colour them with litmus. These nuclei are constant. 



In the alveoli, which lie between the anastomosing branches and also 

 between the lacunae of the canals, are sometimes found numbers of round 

 cells. They do not readily take up hematoxylin, at least I have not 

 often been enabled to find them by means of that stain, but they readilv 

 absorb the litmus colour. When examined by a quarter they appear 

 like round free nuclei ; but if examined very carefully, or with a sixteenth, 

 they are seen to have a thin layer of uncoloured protoplasm round them. 

 They are in fact cells (or nuclei) in which the nucleus (or nucleolus) is 

 disproportionately large for its envelope : they are not constant. In 

 some cords, especially when removed from large children, they are found 

 very scantily ; whilst in the cord of a small eight months' child 

 (Plate 12. fig. 9) I. found them to be extremely abundant. They are also, 

 as in this instance, found far more numerous in some parts of the cord 

 than in others, and in one district of the cord than in another. They are 

 most abundant close to the umbilicus, and in the districts in which the 

 capillaries are seen. They are certainly free in the alveoli ; for I have 

 seen them wandering and exhibiting amoeboid movements on the warm 

 stage, after having taken up the litmus colour. I have never seen the 

 lacunar nuclei exhibit any movements, nor have I ever seen any appear- 

 ance as if they multiplied by division. These round cells may not be 

 confined to the alveoli, however, as they seem scattered over the tissue 

 in the uninjected cord. In the injected cord I have seen them in the 

 alveoli only. In sections taken near the umbilicus they are seen to be 

 most numerous in the vicinity of a small capillary which ran up the 

 cord certainly to as far as half an inch from the ring. Here they are 

 also seen to be of larger size than elsewhere (Plate 12. fig. 11), and to ap- 

 pear close to the mass of blood-corpuscles which, as a clot, occlude this 

 capillary. My inference is that they originate in this neighbourhood 

 (to be afterwards more carefully described) and migrate throughout the 

 cord. They do not ever appear as if they multiplied by division. The 

 walls of this small vessel had no muscular fibre, but seemed to be formed 

 merely by a condensation of the canalicular tissue. 



