194 E. A. Schäfer, 



segmental membranes, the sarcoplasm will here be present in larger 

 amount. x ) 



Assuming' then that the muscle-columns or sarcostyles which are 

 seen in preparations of the dead tissue, and in the wing-muscles even 

 during life, represent pre-existent longitudinal elements, the question 

 still remains to be answered, „Are these elements themselves further 

 divisible?" In other words „Are the sarcostyles fibrillated?" 



In answer to this question it may be stated that it is impossible 

 to detect fibrillation in the fresh condition, but that an appearance 

 of longitudinal striation, which has usually been taken to indicate 

 fibrillation, can sometimes be made out in the sarcostyles of dead 

 muscle after the action of fixing reagents (alcohol , osmic acid, 

 chromic acid). But the appearances of the transverse section of some 

 leg-muscles, e. g., Hydrophilus, vide Eollett, 2nd communication, Fig. 3 

 and those of both the transverse and longitudinal views of the sarcous 

 elements of the wing-muscles, Figs. 28 to 37, render it extremely probable 

 that in all cases this appearance of fibrillation in really due to a tu- 



*) No one has followed out the points of correspondence between the so-called 

 reticulum of ordinary muscle and this inter-columnar substance of the wing-muscles 

 more satisfactorily than Ramon y Cajal (op. cit.), who shows them to be morphologi- 

 cally equivalent to one another. And his figures of the transverse section so clearly 

 show the muscle-columns completely surrounded by sarcoplasmic substance that 

 one marvels to find that so practised a histologist could arrive at any other con- 

 clusion than that the muscle substance is divided up into cylindrical columns, 

 separated by that substance. Doubtless , however , the conclusion he arrived 

 at (vide antea p. 181) is due to the attitude of mind in which he approached the 

 subject of the wing-muscles. Having apparently from the study of the much more 

 obscure structure of the ordinary muscles, come to the decision that the fibre is 

 composed of a contractile reticulum enclosing a continuous non-contractile enchylema 

 in its meshes, and that except in the reticulum there are no pre-existent fibrils 

 present in the muscle substance, he is prepared to find that in the wing-muscles 

 also the part which he rightly shows to be equivalent to the reticulum is the con- 

 tractile part and that the inter-reticular substance (muscle-columns, sarcostyles, 

 „wing fibrils" of authors) is continuous throughout the fibre, that is to say, is not 

 naturally in the form of separate columns and is non-contractile. Had Eamón y 

 ( îajal examined the wing-fibres of insects in the living condition, in a drop of white 

 of egg, in the manner long since recommended by Merkel (Arch. f. mikr. Anatomie, 

 Bd. IX and Bd. XIX), he would have had no difficulty in convincing himself 

 1. that the muscle-columns are pre-existent, 2. that they are contractile, 3. that 

 the sarcoplasm is not contractile; and would thus have avoided the double error 

 into which he has been betrayed. 



