158 DR. E. KLEIN. 



even between the lobules of the same group, the fascicle plates 

 are still considerable both in thickness and breadth, while in the 

 corresponding places of the parotid and submaxillary of the 

 rabbit and guinea-pig, the plates are very insignificant in thick- 

 ness, being represented by few very delicate bundles ; the 

 flattened connective-tissue cells are now the most conspicuous 

 features. This is well illustrated by a comparison of the inter- 

 lobular connective tissue of the parotid of the dog, as represented 

 in fig. 1, with the interlobular tissue of the submaxillary of the 

 guinea-pig. 



Excepting the connective tissue passing into the lobule with 

 the duct and large vessels, there is little of this tissue between 

 the alveoli. In those cases where there is between the lobules 

 a considerable amount of connective tissue, of course arranged 

 as fascicle plates, there is also a correspondingly great amount 

 of connective tissue passing into the interior of the lobules. 

 Thus, for instance, in the parotid of the dog and ape, and in the 

 submaxillary of man, we find delicate fascicle plates continued 

 into the lobule both in company with the chief duct, and also 

 derived from the interlobular septa. But in other cases, e.g. in 

 the parotid and submaxillary of the rabbit and guinea-pig, only 

 delicate connective- tissue bundles and connective-tissue cells are 

 found in these localities. Between the alveoli we meet v/ith the 

 capillary blood-vessels supported by few delicate bundles of 

 connective-tissue fibres, and numerous endotheloid cells of 

 exactly the same nature as those described of the interlobular 

 tissue, viz. more or less branched flattened cells, each with an 

 oval clear nucleus containing a delicate intranuclear reticulum. 

 When removing, by shaking, pencilling, or otherwise, the 

 alveolar epitheHum, we get in many places a clear view of the 

 interalveolar supporting tissue. The basket reticulum of flat 

 cells forming the membrana propria of the alveoli (Boll, Hei- 

 denhain, and others) are seen separated by the capillary blood- 

 vessels, by the above cell plates, and here and there by a 

 delicate fibre bundle. But these latter are in some glands, e.g. 

 parotid and submaxillary of rabbit and guinea-pig, distinct only 

 in the neighbourhood of the intralobular ducts and in the peri- 

 phery of the lobule. Between the alveoli there exists in some 

 instances more distinct than in others, a general homogeneous 

 matrix, in which the capillary blood-vessels, the cell plates and 

 fibre bundles are embedded. This matrix appears in hardened 

 and stained specimens of a definite " body," being slightly 

 stained but transparent. In the human pancreas I can dis- 

 tinctly make it out, and am able to ascertain that, with the 

 capillary blood-vessels, connective-tissue cells and fibre bundles, 

 if any, it forms the one wall for the circum-alveolar lymph 



