W. S. Patton 
153 
ookinetes and encapsuled oocysts of Haemogregarina pythonis ,” as if it 
were absolutely proved by Prowazek that they represent the sexual 
stages of H. pythonis. Why Dr Sambon exaggerates Prowazek’s 
statements I cannot understand, unless he thinks by doing so he will 
strengthen his own position. He now states that in consequence of 
Prowazek’s announcement he has examined some of the specimens of 
P. crotali from Lachesis mutus infected with Ii. seligmanni, and has 
been able to confirm Prowazek’s discovery, and thus complete the life 
history of this haemogregarine. He tells me that I am wrong in 
considering the haemogregarine ookinetes and oocysts found in the 
stomach of Porocephalus pattoni as stages in the development of a 
parasite peculiar to the linguatulid. Dr Sambon surely does not think 
that I would have lost the opportunity of describing the sexual cycle of 
a snake haemogregarine which I found in 1905, and left it to Prowazek 
and himself to re-discover and describe. If Dr Sambon will refer to the 
Annual Report of the Bacteriological Section of the King Institute of 
Preventive Medicine for 1906 he will find the parasite of P. pattoni 
recorded there provisionally as a Gregariue; at present I see no reason 
to alter my opinion. I shall however look forward to reading Dr 
Sambon’s description of the complete life cycle of H. seligmanni ; 
I only hope that he will give us some definite proofs to support his 
statements. 
Dr Sambon, in criticising my remarks on the developmental forms 
of haemogregarines in linguatulids, says, “ Captain Patton is inclined to 
consider all the developmental forms of vertebrate haemoprotozoa found 
within the alimentary tubes of invertebrate hosts as totally independent 
parasites peculiar to these invertebrate hosts.” It is now well known 
that blood-sucking invertebrates are infected with natural parasites 
whose life cycles are very imperfectly known, and as there is at present 
too great a haste to discover and describe the developmental forms 
(sexual cycles) of blood-inhabiting protozoa in the alimentary tracts of 
invertebrates, these natural parasites have been entirely overlooked. 
Recent protozoological literature is full of such mistakes. Knowing 
these facts it is necessary to observe great caution in interpreting the 
forms found in the digestive tubes of invertebrates fed on the blood of 
vertebrates infected with protozoa. This is what I wish to emphasise 
when I disagree with Dr Sambon in his interpretation of the parasites 
of linguatulids; I have however nowhere stated that all the develop¬ 
mental forms of vertebrate haemoprotozoa found in the alimentary 
tracts of blood-sucking invertebrates represent stages in the evolution 
of parasites peculiar to invertebrates. As for Dr Sambon’s reference to 
