REPORT ON MOSQUITOES. 65 



protect these delicate organisms from dessication. Since no 

 encystment occurs with the malarial germ, or with any of the 

 known Haematozoa, we are justified in concluding that direct 

 transmission is impossible for them. Like the seed of a plant, 

 the animal spore must reach a suitable soil before it can germi- 

 nate, and the only suitable soil is the body of its appropriate 

 host." 



In parasitology the terms "intermediate" and "definitive" host 

 liave been applied. In the first case to designate the organism in 

 Which the asexual reproduction occurs and in which the parasite 

 does not reach its full development. The "definitive" host is that 

 in. which the sporozoan becomes sexually mature, conjugates and 

 produces the stage by means of which it may be introduced into 

 the "intermediate" host. Applying these terms as in the past, 

 malaria becomes a disease of the mosquito, one stage of which 

 is passed in man as the "intermediate" host. 



"Nature does not adopt roundabout methods when direct ones 

 will serve her ends. To the parasitologist, therefore, the fact that 

 experiments have shown beyond a doubt that malaria is trans- 

 mitted by mosquitoes is sufficient proof that this is the only means 

 of transmission." 



"We may, accordingly, dismiss once and for all, the time 

 honored but never proven doctrine that malaria germs lurk in 

 damp soil or float in the miasma of swamps, ready to infect man- 

 kind whenever the soil is disturbed or the swamp air breathed. 

 That w-e may get malaria from swamps and in consequence of 

 breaking- the soil cannot be denied ; however, w^e get it, not 

 directly, but because these conditions favor the breeding of Ano- 

 pheles." 



"At the outset it is necessary to define just what is meant by 

 'malaria,' for many and diverse ailments masquerade under this 

 convenient g-uise." Physicians sometimes diagnose as "malaria" 

 a general malaise characterized by a slight fever, which is 

 relieved by administering quinine. "Again, there may be a 'chill' 

 as well as a fever. Even this does not prove a case of malaria, 

 which can be diagnosed with certainty only from the blood. 

 Unless, after reasonably dilig'ent search, the malarial germ (Plas- 

 modium or Amoebula) is found in the blood, it is safe to conclude 

 the disease is not true malaria, no matter what the symptoms. 

 The malarial paroxysm or 'chill' is undoubtedly the most reliable 

 clinical symptom, but it is not infallible." 



"If freshly drawn malarious blood i$ kept at body tempera- 

 ture and protected from the atmosphere, the plasmodia in the 

 corpuscles may be seen to exhibit active streaming or amoeboid 



s MO 



