134 
HEPORT OF TRAVELLING PATHOLOGIST AND PROTOZOOLOGIST 
Morphok)gy 
of embtyos, 
new points 
Experiments 
with Cyclops 
Confirmation 
of Leiper's 
work 
disadvantage of being somewhat tedious, but the results cannot be obtained by any rapid 
method, as the embryos so readily shrink and staining through the cuticle is difficult. 
Prepared in this manner the following points can be made out (Plate IX., fig. 1). There is an 
alimentary canal opening at the anterior end at the mouth, and on the ventral surface near the 
posterior end in a distinct anus. The opening of the anus is a transverse slit on the summit of a 
slight elevation (Plate IX., figs. 6 and (!). The anterior part of the alimentary canal is narrow and 
its wall and the body wall in this region seem to be contiguous. Behind this the canal widens 
out and its wall is much thinner. In this region there is a distinct space between the body 
wall and the intestine. This cavity is not lined by epithelium, but is merely a space between 
tbe single layer of cells forming tbe body wall and the similar layer forming the wall of 
the intestine (Plate IX., fig. 4). This space, which is not a true coelom hut which is similar 
to the space found in other nematodes, is not continued behind the anus, and I was unable to 
trace it forwards round the oesophageal portion of the gut (Plate IX., figs. 5 and 6). The intestine is 
tilled with some granular material, which is often seen escaping from the anus and which stains 
a deep blue with the hsematoxylin. Near the anterior end on the ventral surface is a second 
opening (Plate IX., figs. 1, 3). This is found to be connected with an elongated granular structure 
which runs backwards for some distance under the cuticle and which stains a deejj blue. Often 
some dark staining material can be seen escaping from the opening. Dr. Leiper informs me that 
this is probably the developing excretory system. As far as I am aware, this body has not hitherto 
been described. The pointed tail is filled with a solid mass of cells in which are embedded two 
spherical structures each opening by a distinct pore on the sides of the body just behind the 
anus. Plate IX., tig. 5, shows a view of this region from the right side with only one of these 
bodies in view. Its opening is slit-like and often wider at each end than at the middle, so that 
it reminds one of an elongated figure 8. Prom the ventral surface these bodies are shown in 
Plate IX., fig. fi. I was unable to make out any structure in these bodies apart from a 
granular material. 
Ex2)ariments with Cyclops 
In the neighbourhood of Wau cyclops could easily be obtained, and these were readily 
infected with guinea-worm embryos by placing them in a watch glass together. Prom these 
observations it would appear that the embryos gaiir entrance to the body by piercing it with 
their sharp tails, as a result of their characteristic springy movements, in which the body 
alternately coils up and straightens out. After the cuticle of the cyclops is pierced the 
continued movement of the embryo’s body completes the entrance. It must be stated that 
in no instance was a single embryo followed through the whole course of its entrance, but 
on several occasions different ones were seen at vai'ying stages. In Plate IX., fig. 2, is depicted 
a cyclops with an embryo entering in this manner. This is a drawing made from a 
preparation in Canada balsam, so that there cannot be any doubt that the embryo has in 
reality perforated the cuticle and is not merely lying beneath the cyclops. 
After entering the body the behaviour of the embryos was exactly that described by 
Dr. Leiper. In about six or seven days the movements of the embryos, which had been 
diminishing during this period, ceased altogether. Apparently the number of embryos 
entering each cyclops was limited only by its capacity. The cyclops frequently died from 
the effects of their infection. When the embryos had reached the stage of quiescence their 
activities were at once renewed by placing them in '2 per cent. HCl solution, which had 
the effect of killing the cyclops after a few minutes. The movements of the embryos 
increased till finally they ruptured the body of the host at some spot and escaped to the exterior, 
where they remained active for an hour or more. These escaped embryos were of the same 
