C. H. Treadgold 
121 
before fixation cannot be recommended, for a certain amount of alteration 
has inevitably occurred, while the extent of this will vary with the time that 
has elapsed since death, with the nature and temperature of the surrounding 
medium and so on. These difficulties are best surmounted by fixing the living 
material in hot alcohol, the slides being transferred to 0*9 per cent, saline for 
purposes of mensuration. The chief advantages of this procedure are the 
following: 
(1) Simplicity of technique. 
(2) The shrinkage that occurs is uniform and relatively slight. 
(3) The taking of accurate measurements is greatly facilitated because 
most of the larvae are fixed in complete extension. 
(4) The possibility of their dimensions being altered by complicated 
staining processes is avoided. 
A glance at Table III shows how greatly these measurements are affected 
by the conditions under which they are made. Since the figures obtained from 
the mensuration of dried material are obviously valueless, it would undoubtedly 
simplify matters if those obtained after fixation in 70 per cent, alcohol at 
60-65° C. and examination in 0-9 per cent, saline were stated as often as 
possible in addition to the figures obtained from living material. 
Table III. 
Measurements of Microloa loa and Microloa papionis compared in microns. 
Ml. loa 
Length Breadth 
Fresh material. 210-280 7-7*5 
Low (1911) 
Smears fixed wet in hot alcohol ... 208-254 — 
Stephens (1916) 
Dry unfixed smears treated with azur II — — 
Dry smears fixed with absolute alcohol 131-166*5 — 
Stephens (1916) 
Ml. 
papionis 
Length 
Breadth 
270-330 
6*5-7 
270-330 
About 5 
245-310 
— 
178-265 
— 
Morphology of the larvae taken from the blood. In fresh preparations, the 
movements of the larvae are indistinguishable from those of Ml. loa. After 
dry fixation, they are never disposed in such graceful curves as the larvae of 
Filaria bancrofti ; both in thin and thick smears their attitude more nearly 
resembles that of Ml. loa, but their tails are rather more pointed (Plate VIII, 
fig. 1). I seldom noticed the presence of a sheath, although it was occasionally 
very distinct both in fresh and in stained preparations; as in Ml. loa, it is 
comparatively short and keeps its form during the movements of the larva. 
The cuticle is transversely striated, and its appearance closely corresponds 
to Fiilleborn’s (1913) diagram of the cuticle in Ml. loa. The nuclei of the 
subcuticular cells are few in number (Plate VIII, figs. 3, 4, N.S.C .); I never saw 
