68 0. F. MAESHALL. 



joining the dark granules are only parts of the optical longi- 

 tudinal sections of the walls of the sarcoplasma and are only 

 seen at high focus; and that they do not lie in a line with the 

 dark granules, but alternate with them, the dark granules being 

 only seen at low focus. The granules which appear at high 

 focus he considers to be thickenings of the sarcoplasma. 



The above diagrams, modified from Rollett^s figures, will 

 make these points clearer. Diagram B represents the appear- 

 ance at low focus, and diagram A the appearance at high focus 

 according to E-oUett. In B the muscle-columns appear dark 

 and the sarcoplasma light ; in A the sarcoplasma dark and the 

 muscle columns light. 



In the same way he states that the rows of granules seen in 

 gold preparations are thickenings of the sarcoplasma lying 

 between the thin segments of the muscle-columns, and that the 

 true row of granules which correspond to and are parts of the 

 muscle-columns are only seen at low focus, and then do not lie 

 in a line with the dark lines, but alternate with them. 



He describes the same appearance at low and high focus in 

 hardened muscle, and states that Melland and Van Gehuchten 

 place the granules alternating with the muscle-columns, whereas 

 they are really in a line with them. 



In short, he concludes that a network does not exist, and 

 that the appearances described by Melland, Van Gehuchten, 

 and myself are due to errors in the interpretation of micro- 

 scopic appearances and confusion of high and low focus (" Ich 

 komme also zum Resultate dass ein Netzwerk im Sinne von 

 Melland, Marshall, und Van Gehuchten und ein Euchyleme 

 im Sinne des Letzteren in der quergestreiften Muskelfaser 

 nicht existirt," p. 262). 



In answer to this criticism I venture to make the following 

 observations. 



1. If the appearance of the network in fresh muscle is due 

 to the optical appearance of the " sarcoplasma '* at high 

 focus, there must always be a double row of granules — one on 

 each side of Krause^s membrane. (I use this term for the sake 

 of convenience, and take it to represent the row of dark 



