The Structure and Functions of the hîemolymph Glands and Spleen. 31 



The method originally intended was that used by ChevreP) for 

 the display of the sympathetic nerve fibres in fishes. Osmio acid is 

 painted on the dissection, with the result, in fishes, that the nerves 

 stain black while surrounding tissues remain white. In attempting 

 this method upon mammalian material the result has been reversed; 

 the nerves for a long while remain white while the surrounding fat 

 becomes black. Painting with corrosive sublimate, after the osmic 

 is washed off with distilled water, increases the contrast. 



A large tangled plexus of nerves issues from a ganglion (semilunar 

 ganglion) over the aorta, above the renal vessels (pi. I. fig. 7); the 

 fibres run along the bloodvessels of the neighbourhood, forming minor 

 plexuses. Those with which we are chiefly concerned accompany the 

 splenic and renal vessels; from these minor plexuses, numerous off- 

 shoots are given to the corresponding splenic and renal groups of 

 glands. In many cases a plexus is formed around the gland, in others 

 fine fibres may be traced into the substance of the capsule. Other 

 fibres proceed from the ganglion more directly, while in the case of 

 the splenic group, several fibres arise from the solar plexus itself 

 (or more correctly from that portion of the plexus lying on the aorta 

 anterior to the ganglion). 



Several attempts have been made to display the nerve supply to 

 the interior of the gland, using the gold chloride and formic acid 

 method of Löwit. I can at present only state that the capsule has 

 an abundant nerve supply, the fine nervous fibrils breaking up in 

 this tissue and in the trabeculae, and ending in delicate twigs, to 

 which are occasionally attached small angular enlargements. 



The nerve supply of the organs under consideration is so abun- 

 dant, as to lead to the conclusion, that a considerable influence must 

 be exercised by the nervous system, probably in close connection with 

 the changes taking place in the glands. Stimulation of the gland itself 

 or of the nerves supplying it, in the living animal, causes slight but 

 distinct paling of the red patches representing the sinuses, while at 

 the same time the whole gland suifers a slight diminution in bulk. 



^) Archives de Zoologie expér. et gén. 2e serie, tome V. bis. 1887. Supplé- 

 mentaire. 



