146 
Haemogregarines 
interpretation of Lankester’s observations without convincing evidence 
to prove it; further I can find nothing in Dr Sambon’s papers to show 
that he has even studied this parasite. These however are just his 
methods, and throughout his papers he interprets other workers’ observa¬ 
tions to suit his own ideas. The principle seems to be, Dr Sambon 
makes the free vermicides of haemogregarines sporonts, therefore they 
must be sporonts. 
As I have studied L. minima I am in a position to examine any 
evidence in support of Dr Sambon’s view. It is well known that on 
examining, in the fresh condition, the blood of a frog infected with this 
haemogregarine, the parasites soon leave the red blood corpuscles and 
may be seen as free vermicides moving about in the plasma. On feeding 
a species of Glossiphonia parasitic on Rana tigrina, and on examining its 
crop contents, it was found that the parasites had similar^ liberated 
themselves, and were actively moving about in the fluid. Now if these 
parasites represent the sporonts it is only natural to expect that they 
would, after some unknown time, begin the process of sporogony some¬ 
where in the leech’s alimentary tract, and according to Dr Sambon we 
should expect to find them in couples lying side by side. Later they 
would have fused together and then produced an ookinete, which would 
eventually result in a cyst containing sporozoites. Now nothing of the 
sort takes place, the free vermicides (Dr Sambon’s sporonts) do not 
undergo any such process, for they can be found in much the same 
condition in the crop of the leech for several days after it has sucked the 
blood of an infected frog. What then happens to them and how does 
the parasite complete its evolution ? From some evidence I have been 
able to gather I believe the parasites make their way to the sheath of 
the proboscis, and are then inoculated into the next frog the leech bites. 
This is the only conclusion I can come to at present, and though it may 
seem strange to Dr Sambon that this parasite does not undergo sporogony 
in its invertebrate host, no amount of observations on the vermicules in 
the leech can demonstrate such a cycle. I suppose Dr Sambon would 
tell me, that had he examined the vermicules of L. minima, he would 
have been able to say whether in this case the sporonts exhibit any 
sexual differentiation, for he now tells me, that as he has not seen the 
leucocytic parasite of the hare, he is not in a position to say whether its 
sporonts do at any time exhibit sexual differentiation. I begin to wonder 
now whether there has been something wrong with the methods and 
technique I have employed in studying these parasites, because I am 
unable to find their sporonts. It is therefore to be regretted that Dr 
