16 H. B. FANTHAM. 
S. anodontz is usually about 40 u long and 0°7 uw broad. 
Its ends are pointed, and it possesses a spirally wound undu- 
lating membrane, and a diffuse nucleus of chromatin rodlets 
arranged on a more faintly staining spiral. 
MovEMENTS OF THESE SPIROCHATES. 
Previous accounts of these phenomena are most meagre ; 
yet descriptions of such movements are much to be desired, 
and would be of the utmost importance in helping to decide, 
for example, whether the pathogenic organism, 8. ober- 
meieri, of human relapsing fever is really a Spirillum or a 
Spirochete. I will now attempt to supply this omission, to 
some extent, by giving as full account as I can of the move- 
ments of 8. balbianii and 8. anodonte. 
This is, however, a question of great complexity, and-the 
movements are most difficult to analyse and interpret, both 
on account of the rapidity of the motion and of the smallness 
and extreme tenuity of the organism. One naturally turns 
for aid in solving the problem to slowly moving and compara- 
tively quiet forms, or to forms partially entangled among 
débris for a short time, but it must be constantly borne in 
mind that the movements of such organisms may not be 
quite normal. 
S. anodonte moves rather more rapidly than S. bal- 
bianii, indeed, so quickly that it is almost impossible to 
analyse its motion when travelling at full speed, and each of 
them moves faster than most Trypanosomes. The move- 
ments are much the same whether the organism be examined 
inside the crystalline style or moving freely in the lumen of 
the gut. 
The path may be either in a straight line or more or less in 
involved, the term was not substituted in the body of the text, but it would 
have been preferable to have used it throughout the memoir. 
1 Specimens vary from 30 yp to 60 pm in length, and from 0°7 w to 1 w in 
breadth. 
