498 Mr. II. B. Fantham on Spirochajta 



There is a cap or nodule attached to each end of the 

 periplast in S. Balhianii which stains pinkish with Giemsa's 

 solution, and which may be a " basal granule." 



The chromatin granules of S. anodontcs are difficult to see, 

 the whole organism being much smaller, but the nucleus 

 seems to conform to the general arrangement of that structure 

 ill S. Balbianii. 



The Undulating Membrane. 



This structure does not extend quite to the ends of the 

 organism. There is some difference of opinion as to its 

 nature, but its presence is a characteristic feature of the 

 genus Spirocha'ta as now defined. 



It is, I believe, a spirally wound membrane or lateral 

 outgrowth of the ectoplasmic periplast, and is composed of 

 longitudinally arranged fibrillse. These fibrillse are contractile 

 and may be termed " myoneme fibrillfe," though the term 

 " myoneme " is perhaps not a happy one. There appear to 

 be some eight or nine principal fibrils, and many less evident 

 ones parallel therewith, all of them apparently longitudinally 

 arranged. The border of the membrane is thickened and 

 stains well with chromatin stains. I agree with Perrin that 

 the membrane possesses a chromatic border. 



In slowly moving parasites the edge of the membrane, and 

 even the membrane itself, is easily seen (Zeiss DD and ocular 2) 

 in life. Such forms are curved into about two or three 

 sinuosities only, and the membrane can be seen in the troughs 

 of these, loosely arranged and not contracted close to the 

 body. 



It has been suggested by Laveran and Mesnil that this 

 structure is not really a membrane, but a sheath, only 

 loosely attached, if at all, to the body of the organism. This 

 matter is most difficult to settle, and is certainly not to be 

 passed over lightly by mere dogmatic assertion either one 

 way or the ether. However, one can see in preparations the 

 spiral arrangement of the membrane in many cases, and its 

 actual crossing over the body from one side to the other, both 

 above and below. And, furthermore, the organism possesses 

 a distinct spiral motion, evidently guided by the spiral 

 arrangement of the membrane. Again, if the body moved 

 more or less freely inside a sheath one might expect to see 

 some signs of differential motion between the organism and 

 its sheath. I have never seen such during my investigations. 



It seems to me, then, that this structure is a membrane, 

 spirally wound round the body, and is an outgrowth of the 

 periplast. It is composed of elastic fibrils and is contractile, 



