1874.] the Lymphatic System of the Lungs. 143 



somewhat different. The nodules were seen to differ in their structure 

 from those in the former series in the following respects. In some of them 

 it was easy to recognize that they represented a number of alveoli very much 

 distended by a fibrinous substance similar to that described above, which 

 included granular material and a number of small cellular elements ; the 

 trabeculse of these nodules (that is, the interalveolar tissue) were slightly 

 thickened and contained young cells, their capillary blood-vessels being not 

 completely permeable and not easily distinguishable. Besides these there 

 were nodules of which only the central alveoli were in the state just men- 

 tioned ; whereas in those situated more peripherally the fibrinous material 

 was no longer to be discovered, but they were filled in one or other of the 

 following ways : first, by spherical nucleated elements, many of which 

 could be still recognized as epithelial cells, by their size, granulation, and 

 nucleus/and some of which contained two nuclei. In these places, the inter- 

 alveolar trabeculsB were thickened in a very marked manner, exhibiting 

 all the appearances of an infiltrated tissue that is to say, a more or less 

 distinct reticulum of nucleated fibres, in the meshes of which lay small 

 lymphoid corpuscles very readily stained by logwood or carmine. Or, 

 secondly, they were filled by one large multinucleated mass or giant cell. 

 In the latter case the giant cell, or rather the multinuclear protoplasmic 

 cylinder, contained the nuclei either regularly distributed in its periphery, 

 or all crowded together in the central part of the mass. As regards the 

 nuclei, it may be said that they stain readily ; they are relatively small, 

 sharply outlined, and contain one or two nucleoli. The protoplasm of the 

 giant cell is tinted slightly yellowish, does not stain in haematoxylin, and is 

 very regularly filled with small granules of equal size. As regards the deve- 

 lopment of these giant cells and their nuclei, I must first contradict those 

 authors who say that they originate generally by a free-cell formation in 

 the veins, as well as those who make them originate in lymphatic vessels ; 

 for I have followed their development from the epithelial cells of the 

 alveoli with all possible certainty. I have been able to make out that the 

 whole epithelial lining of an alveolus becomes fused together into one pro- 

 toplasmic lump which fills out the alveolar cavity, and the nuclei of which 

 rapidly divide, remaining, however, in their original places, viz. peripheral. 

 We have here a protoplasmic cylinder the transverse section of which 

 shows a peripheral ring of nuclei. But a single epithelial cell may 

 also become transformed into a multinuclear giant cell : one or the 

 other epithelial cell increases rapidly in size (probably at the expense of 

 its fellows) ; its protoplasm^becomes enlarged as well as its nucleus ; then 

 this nucleus gives rise by cleavage, or by budding, to a number of small 

 nuclei, so that it is transformed into a number of nuclei lying in the 

 middle of the cell. [I have little doubt that Klebs would be much inclined 

 to regard the very regular granulation of the giant cells previously men- 

 tioned, as being due to the presence of micrococci ; such an assumption, 

 however, could not easily be proved. A substance filled very regularly 



