78 
Filaria loa 
embryo with its sheath. We observed some of these coiled embryos 
uncoil and stretch the sheath which contained them. 
Of these thousands of embryos in water on the glass slide we made 
a number of fixed preparations to be variously stained. Others were 
placed in wet human blood preparations sealed with vaseline. 
Some were injected into the subcutaneous tissues of a guinea-pig. 
The water containing some of them was given to another guinea-pig to 
drink. The guinea-pigs died recently but no cause of death could be 
discovered. 
I did not succeed in getting the embryos to butt their way out of 
their sheaths after heating a blood preparation which had been chilled 
on ice as described by Manson. Nor was I successful in reviving 
embryos which had been dried as suggested by the same author. In 
heating a wet blood preparation slight currents may be set up which 
cause the appearance of slight motion on the part of the embryo and 
give the appearance of butting. . 
Measurements 
Coiled embryos 0‘051 x 0-036 mm. 
Embryos 0-006 x 0-3 mm. 
Average projection of sheath anteriorly 0-009 mm. 
,, ,, ,, ,, posteriorly 0-009 mm. 
Anterior V spot 0-09 mm. from head end. 
Posterior ,, 0-06 mm. from tail end. 
Livon and Penaud give the length as 0'3 to 0'35 mm. and the width 
as 0‘005 to O'OOTmm. The maximum diameter of the embryos, 0'006 mm., 
is maintained with very slight diminution until a point 0'24 mm. from 
the head end is reached where the body commences to taper to the 
posterior extremity. The posterior extremity is rounded. It is not 
sharply pointed and we cannot conceive such a tail being folded upon 
itself within the sheath as described in the table given by Neveu- 
Lemaire. At the anterior extremity, which is broadly rounded, there are 
two highly retractile black specks. 0‘09 mm. from the head end is the 
ovoid mass which presents the anterior V spot. This ovoid mass causes 
a slight bulging of the body on three sides but not on the fourth as it 
does not extend deeper than the plane of the central longitudinal axis 
of the body. Within this clear highly refractile mass there are two 
black granular specks separated sufficiently to give rise to the V (spot) 
which is an optical effect. The point of the V is directed to the 
periphery. 0'06 mm. from the tail end is a similar but smaller ovoid 
