on the Structure of the Muscular Fibril. 371 



Here observers, not thus prepared, mistook the winds of spirals 

 for varicosities or beads ; for instance, Bowman, who in single 

 fibrillar figures as such what were evidently spirals*. Some of 

 his delineations of fasciculi, also, afford beautiful illustrations of 

 spirals distorted in manipulation, of which the appearance he 

 aptly compares to " engine-turning" is an exquisite example. I 

 can attest the accuracy of those delineations of fasciculi. They 

 are faithful representations of nature ; but, at the same time, 

 they are proofs of the existence of a structure, which for the 

 reason just mentioned the delineator did not understand. As 

 for the "discs" of Bowman, they are transverse slices of fasci- 

 culi in full contraction, cut off where least capable of withstanding 

 violence in manipulation. At such parts each spiral of a pair 

 is then in contact with its fellow ; there they cross and antago- 

 nize each other ; in full contraction this crossing is at the acutest 

 angles, and consequently there they cut each other through. And 

 if maceration has been used, a practice too common with some 

 observers, no wonder if the " discs" present little more than 

 particles ; for it is of particles that the spirals are composed. 



How true the words of Huschke, that " in order to under- 

 stand an organ or the structure of a tissue, we must inquire : 

 How did it originate V 3 When muscle, a tissue more compli- 

 cated than any other, has been thus dealt with by observers 

 generally, they will understand and acknowledge its spiral struc- 

 ture ; but not till then. 



Since Bowman wrote, observers, in their endeavours to reach 

 the ultimate structure of the muscular fibril, have actually gone 

 too far. They passed over what really admits of examination — 

 the mature fibril, and arrived at what almost defies the micro- 

 scope — its embryo; mistaking and delineating for the fibril a 

 row of quadrilateral particles, the mere elements thereof; mis- 

 taking for the chain, as it were, a row of half-formed links 

 destined to compose the chain. It is not surprising, that, as the 

 embryo fibril passes through many stages in the course of its 

 development, it should have presented different appearances to 

 different observers, producing a corresponding variety of descrip- 

 tions and drawings. And I certainly cannot wonder that in a 

 row of quadrilateral particles no one could discern my twin 

 spirals ! Without therefore questioning the accuracy of these 

 observers in describing and delineating what they saw, I main- 

 tain, in the first place, that it was impossible for them to agree 



* Phil. Trans. 1840, plate 16, figs. 10, 12, 15, drawings copied by myself 

 into Miiller's Archiv, 1850, Taf. 17, and into the Phil. Mag.1852, Plate I., 

 for the purpose of showing them to represent spirals. 



