ccxxiv SECRETING GLANDS. 



even of a single one, with a duct, minute in size and sparingly branched, 

 to correspond. In fact, a small racemose gland resembles a fragment of a 

 larger one. 



A great many compound glands, yielding very different secretions, belong 

 to the racemose class. As examples, it will be sufficient to mention the 

 pancreas, the salivary, lachrymal, and mammary glands, with the glauds of 

 Brunner already referred to, and most of the small glands which open into 

 the mouth, fauces, and windpipe. From the description given of their 

 structure, it will be understood why the term " conglomerate glands" has 

 been applied especially, though not exclusively, to this class. Their smallest 

 lobules were called acini, a term which has also been used to denote the 

 saccular recesses in the lobules, and indeed the word adnus, which originally 

 meant the seed of a berry or the stone of a grape, or sometimes the grape 

 itself, has been so vaguely applied by anatomists, that it seems better to 

 discard it altogether. 



Of the tubular compound glands, the most characteristic examples are the 

 testicle and kidney. In these the tubular ducts divide again and again 

 into branches, which, retaining their tubular form, are greatly lengthened 

 out. The branches of the ducts are, as usual, formed of a limitary or 

 basement membrane (membrana propriety, lined by epithelium, and in 

 contact, by its opposite surface, with capillary blood-vessels. By the 

 multiplication and elongation of the tubular branches a vast extent of 

 secreting surface is obtained, whilst, to save room, the tubes are coiled up 

 into a more or less compact mass, which is traversed and held together by 

 blood-vessels, and sometimes, also, divided into lobules and supported, as 

 in the testicle, by fibrous partitions, derived from the inclosing capsule of 

 the gland. In consequence of their intricately involved arrangement, it 

 is difficult to find out how the tubular ducts are disposed at their extre- 

 mities. It seems probable, however, that some are free, and simply closed 

 without dilatation, and that others anastomose with neighbouring tubes, 

 joining with them in form of loops ; in the kidney, little round tufts of 

 fine blood-vessels project into terminal or lateral dilatations of the ducts, 

 but without opening into them. 



The human liver does not precisely agree in structure with either of the 

 above classes of compound glands. Its ducts, which are neither coiled nor 

 sacculated, would seem to begin within its lobules, in form of a network 

 occupying the interstices of the reticular capillary blood-vessels, which also 

 are peculiar, inasmuch as they receive and transmit venous blood. 



Lastly, there are certain little bodies of doubtful nature, connected with 

 the mucous membrane of the intestine?, and known as the solitary and the 

 agminated glands, which differ from all those hitherto spoken of, inasmuch 

 as they are small saccules without an opening. Some anatomists are of 

 opinion that they discharge their contents, from time to time, by bursting ; 

 whilst others, without denying the possibility of this, are disposed to take 

 a different view of these glandular bodies, and (as, at any rate there are no 

 ducts) refer them to the class of " ductless glands," under which head they 

 will be again adverted to. The full description of these glands, as well as 

 of the peculiarities in the structure of the liver and kidney above referred 

 to, belongs to the details of special anatomy. 



Besides blood-vessels, the glands are furnished with lymphatics, which 

 in the compound glands proceed from lacunar lymphatic spaces within, as 

 already stated (p. clxxxiii. ). Branches of nerves have also been followed, 

 for some way, into these organs, and the well-known fact, that the flow of 



