1902.] NATURAL SCIENCES OF PHILADELPHIA. 345 



which are readily distinguished by color, do not contribute directly. 

 Some of these appear to dissolve without being confined to a globule 

 (as in the bottom of fig. 15), to be added to the interalveolar sub- 

 stance which precipitates in the form of very fine granules. Close 

 comparison of this with the precipitate fi'om the globules, as well 

 as close scrutiny of the precipitate found in the lumen, fails to 

 reveal any difference corresponding to granules and globules. 



It would be unwise to attempt, from the facts thus far reached, 

 to show that there is no chemical difference between the various cell 

 constituents which ultimately share in the formation of the secre- 

 tion, or still more that no corresponding differences are retained 

 throughout the existence of the secretion. There is every reason 

 for thinking that the secretion is far fi-om simple in nature. So far 

 as they bear on the occurrence of fat, however, the facts just re- 

 hearsed seem to speak very positively. Both Weber and Frenzel 

 base their assertion that the globvdes contain fat on the osmic reac- 

 tion and on the action of fat solvents (ether). Nothing is here urged 

 against the facts alleged by these authors. What seems fatal against 

 concluding therefrom that the substance in question is pure fat is 

 that, as we have seen, it is never represented in the coagulum of 

 the secretion by globular spaces such as fat ought to leave, and 

 such as it always does leave when dissolved after fixation. The 

 globular masses which sometimes come out of the cell as such, and 

 do exist in the fresh secretion as oily-looking drops, invariably, so 

 far as my observation goes, precipitate as a dense coagulum, not to 

 be distinguished from the remainder of the secretion. What then 

 is the nature of the globules ? Aside from their oily appearance, 

 nothing occurs in the literature reviewed which throws much light 

 on their nature as they are to be seen in the fresh condition. Sufii- 

 cient prominence has not been given either to the fact that in this 

 condition they are to be seen in all sizes. They are usually much 

 clearer looking than the zymogen granules, but even in this respect 

 the limits are not sharp. Frenzel mentions the fact that the oil 

 globules in lone, Gyge, Iclotea hedlca and Sphceroma have almost 

 always a definite color, " namely, in the first three greenish-yellow 

 (ivle das Secret), in the least one a brownish -yellow." 



The conclusion which appears very evident from the foregoing is 

 this : zymogen granules are merely young stages of the large glob- 

 ules or, conversely stated, the globules are but a matured state of 

 the zymogen granules. The difference as to form, color, behavior 



