91 



occur in the patient's blood only after 6-7 days ; at the time they 

 first appear they are capable of further development in the mosquito. 



The development of the sexual generations of all three plasmodia 

 is most rapid between 24° and 30° C. [75 • 2°-86° F.] . A higher temper- 

 ature than 30° C. did not materially accelerate such development 

 in P. vivax and P. praecox and proved harmful to the life of the 

 mosquito. Below 24° C. such development was materially and rapidly 

 checked, until it ceased at 16° C. [60-8° F.]. 



The occurrence of infection was not affected when the mosquito, 

 immediately after feeding, was exposed to a low temperature for a 

 short time. Such an exposure seemed indeed, like the presence of 

 quinine in the blood, to promote the occurrence of infection. The 

 gametes that had already begun development at an optimum temper- 

 ature were not affected by a low temperature of 60 • 8° F. if exposed 

 to it only for a short time ; but after a prolonged exposure to a con- 

 tinuous low temperature the sporozoites failed to develop. 



Quinine in the blood containing the gametes or in the blood used 

 later for feeding the mosquito was not detrimental to the development 

 of the sexual generation, and malaria parasites resulting from the 

 bite of such a mosquito were not resistant to quinine. 



As regards the production or non-production of the infection in 

 the mosquito it is immaterial whether the bite occurs during the 

 latent period or not, nor does its occurrence during any one of the 

 febrile attacks of the patient or during any one phase of them matter 

 at all. Mosquitos, already infected, can acquire a new infection of 

 the same or other strain of gametes. 



Whatever temperature the infected mosquitos were kept at, they 

 did not transmit malaria before the tenth day. In all cases, except 

 where quinine prophylaxis was resorted to, the bite of a mosquito, 

 of which the salivary glands contained sporozoites, transmitted 

 malaria, and a single bite sufficed. The incubation periods observed 

 were 10 days for P. vivax and 7-11 days for P. praecox. By adminis- 

 tering quinine during the incubation period the latter was prolonged. 



In these experiments no apparent influence on the incubation period 

 of experimental malaria, on its severity, or on the amount of quinine 

 required to repress it, was traced either to the number of the mosquitos 

 causing inoculation, the degree to which they were infected, or the 

 temperature at which they were kept. 



The malarial parasite found in artificially infected cases was always 

 that occurring in the infecting mosquito, and the results of the various 

 experiments justify the assumption that there are three different 

 malarial plasmodia. 



No data were obtained showing that either man or mosquito can 

 develop an immunity to malaria. 



Quinine, either in daily doses of 0-5-1 gm. or in 5-6 day doses of 

 1-5 gm., can destroy an existing infection. 



ScHiLLiN G (V.) . Kriegshygienische Erfahrungen in der Turkei (Cilicien, 

 Nordsyrien). [Experiences in Military Hygiene in Turkey (Cilicia 

 and North Syria).] — Beihefte Arch. Schiffs- u. Trop.-Hyg., Leipsic, 

 XXV, no. 3, 1921, 41 pp., 2 figs, 4 plates. [Received 15th February 

 1922.] 



The fines under the author's supervision extended from Bozanti 

 in the Taurus eastwards to Mardin on the Tigris, and from Aleppo 

 southwards to Damascus. 



(6001) h2 



