STUDIES ON THE PANCREAS OF THE GUINEA PIG 359 



tion is apparent when one examines closely this portion of the 

 cell under the high power, when it is seen that the striation is 

 due to the fact that there are in the cell unstained areas shaped like 

 the filaments observed in the fresh cell after staining with janus 

 green. The striation seen in this preparation, then, is due to the 

 fact that we have in the base of the cell a continuous basophile 

 substance, in which rod-like elements are imbedded. When the 

 latter are dissolved, they leave irregular spaces in the continuous 

 substance. When they are preserved but remain unstained, the 

 spaces they occupy appear as clear rod-shaped spaces in the con- 

 tinuous substances and so give a deceptive appearance of longi- 

 tudinal striation. 



In preparations which have been fixed in solutions containing 

 a sufficient amount of acetic acid to destroy the rods, a totally 

 different appearance is presented by the basal zone. In acetic 

 sublimate or Zenker's fluid preparations, the whole of the basal 

 basophile material is found to be broken up into a feltwork of 

 fine filaments which are wholly different from the coarse rods 

 seen in the janus green preparations. These filaments, while 

 often running parallel to the axis of the cell, are also often found 

 forming an intricate skein running transversely in the base of the 

 cell. These are the familiar basal filaments of Solger or the ergas- 

 toplasmic filaments of Prenant, Garnier, Bouin, etc. 



The question now arises whether the homogeneous basophile 

 material seen in the chrome sublimate preparations or the fine 

 filamentous material seen in the acetic sublimate fixations is the 

 true structure present in the living cell, or to express it differently, 

 whether the filaments seen in the acid fixations are pre-existent 

 in the living cell, or artefacts produced by precipitation. I have 

 tried to obtain an answer to this question, but without success. 

 The most that I can say is that I have been unable to see these 

 basal filaments of Solger in the living cell, though I have studied 

 such cells in native serum and in salt solutions of different compo- 

 sition and concentration. They are not visible in preparations 

 fixed in neutral formaldehyde, or osmic acid, or in fluids contain- 

 ing these substances provided the acetic acid is kept low. On 

 the contrary they are visible in solutions containing a large pro- 



