412 



batlied by the chyle or lymph. This gi-anular layer being continu- 

 ous in both directions with the scale-hke epithelium of the extra- 

 glandular lymphatics, it is therefore merely a developed form of this 

 epithelium. 



Mr Goodsir then stated that the opinion of those anatomists who 

 hold that the intra-glandular lymphatics form a net-work, is correct. 

 In the glands in which the meshes of this net-work are elongated, 

 the vessels, even after forcible injection, never assume the cellular 

 appearance. In those glands again, or in those parts of glands in 

 which the meshes are roimded or equilateral, the injection of mer- 

 cury produces the appearance of globular cells. In other lymphatic 

 glands, a process of absorption, similar to that which occurs in the 

 maternal vascular system of the human placenta, reduces the meshes 

 of the lymphatic net -work to mere threads or bars, and converts one 

 or more shoi-t lymphatic bi-anches into one multilocular cavity. All 

 these varieties are modifications of the simple net-work. 



The ultimate capillaries of the blood-vessels form very fine net- 

 works on the external surface of the crerminal membrane of the intra- 

 glandular lymphatics. The anatomical relations of this capillary net- 

 work, and the germinal membrane and granular substance of these 

 lymphatics, are identical with those of the vessels, membrane and 

 secreting epithelia of true glands. 



One of the functions of the granular substance, the author stated 

 to be the secretion of chyle and lymph corpuscles ; but, as these are 

 also formed in other parts of the lymphatic system, he reserved his 

 observations on this part of the subject for a futui-e occasion. He 

 concluded by observing, that the structure he had described afforded, 

 in his opinion, satisfactory evidence, 1st, That the lymphatic glands 

 are merely net-works of lymphatic vessels, deprived of all their 

 tunics but the internal, the epithelium of which is highly developed 

 for the performance of particular functions ; and, 2d, That these 

 peculiar lymphatics have a fine net-woi-k of capillary blood-vessels in 

 close contiguity with their external surfaces, for the purpose of af- 

 fording matter for the continued renovation of the epithelium. 



3. On the Determination of Heights by the Temperature of 

 Boiling Water. By Professor Forbes. 



The investigations in this paper were made in order to reduce 

 certain observations on the boiling point of water, made by the au- 

 thor in the Alps, in 1842. 



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