THE LEUCOCYTES IN ORGANIC FUNCTIONS. 713 



cells designated as 'alveolar epithelia' are variously altered 

 forms of leucocytes. The protoplasm very frequently shows 

 fine- or coarsely- granular fatty metamorphosis, and is charac- 

 terized by the strongly refractive index" Again, while Len- 

 hartz expresses his belief that the positive identification of 

 the "alveolar epithelia" is "extremely difficult," he states that 

 he understands thereby "the large oval or round polygonal 

 cells, three to six times as large as a white blood-corpuscle, 

 which are found in almost every sputum. The usually large 

 cell-body is coarsely granular, and contains one or several 

 vesicle-like nuclei." The true identity of epithelium of the 

 alveoli and, therefore, of the lobule of which they form part, 

 now seems clear, if interpreted in the light of the data we have 

 submitted: The cells to which Lenhartz refers, i.e., the lolular 

 epithelial cells, are aggregates of the polynuclear neutrophiles and 

 of the daughter-cells of the latter, the eosinophiles. 



We have seen that the neutrophiles start from the intes- 

 tinal canal; that Macallum and L. F. Barker found leucocytes 

 gorged with iron in this region; and, finally, that some bilirubin 

 at least is recovered from the intestine obviously, now, by leu- 

 cocytes. We have traced the latter from the intestinal canal, 

 through the portal system, liver, hepatic veins, heart, thence 

 to the alveoli. After giving the formula of haemoglobin, Pro- 

 fessor Foster writes: "It will thus be seen that haemoglobin 

 contains, in addition to the other elements usually present in 

 proteid substances, a certain amount of iron; that is to say, the 

 element iron is a distinct part of the haemoglobin molecule, a 

 fact which of itself renders haemoglobin remarkable among the 

 chemical substances present in the animal body." Kanthack 

 and Hardy noted, as previously stated, that "in fluid prepara- 

 tions the granules have a brilliant, greenish luster" a charac- 

 teristic of fine haemoglobin crystals. Haemoglobin is readily 

 soluble in blood-serum, as are the granules, we have seen. 

 Ether coagulates haemoglobin; it caused, in Milroy and Mal- 

 colm's experiments, 46 the granules to lose a part of their re- 

 fractive power, even when boiling ether was used. The proteid 

 constituents of the granules of the neutrophiles, myosinogen 

 and fibrinogen, belong to the globulin group. 



" Milroy and Malcolm: Loc. cit., p. 112. 



