1902.] NATURAL SCIENCES OF PHILADELrHIA. 301 



papers ^vith lower powers as lines (" dicken granuliii-ea streifig 

 erscheiuenden Zone " ), he now makes out to be a " fadiges Balkeu- 

 werk dessen eiuzelue Saulchen ausserdem nicht glallraudig siud 

 souderu seitlichen Zackeu haben, durch deren gegenseitige Verbin- 

 dungen ein zartes netziges Weseu zwischen ilinen entsteht." Ide 

 says, " The partisans of the fibrillar struclure of protoplasm as 

 opposed to the reticulated may see here an object very favorable to 

 their thesis" (/. c, p. 158). He recognized, however, as did 

 Leydig, the falsity of such a view, and both autliors connuit them- 

 selves to the reticular structure. 



Later writers also have described this structure more or less 

 explicitly. McMurrich saj^s : ' ' The cytoplasm in young specimens 

 has a uniform finely reticulated structure, but this is replaced in the 

 adult by a much less uniform arrangement." Couklin says, in 

 speaking of the disappearance of the nuclear membrane : ' ' The 

 cyto-reticulum is continued into the nucleus," etc. Schouichen 

 finally accepts this structure also, and Hardy (18) figures a "net" 

 struclure for the fixed cells of Oniseus. 



A B 



ife*: 



W-' 



Fig. 5. — Optical seclious of: A, cytoplasm ; and B, nucleus of median 

 absorbing cells of Porcellio, showing alveolar structure. Drawn with 

 camera lucida from fresh cells, X 925. 



None of the authors named seems to have studied the fresh cells. 

 If a fresh intestine be mounted in blood (see page 280). and one at- 

 tempts to draw the structure as it may then be seen with high powers, 

 he will soon be convinced that the reticular is not the true structure. 

 In all cases I have by this method found the structure to be alveo- 



