March 16, 1906.] 



SCIENCE. 



409 



even the brain ; hence, many of the cerebral 

 symptoms. This parasite is the third form 

 of malarial parasites. There may be a 

 fourth form which causes what we now 

 call yellow fever, and like many other dis- 

 eases it may become obsolete as to name 

 and possibly be classified as malarial. I 

 have almost at times convinced myself that 

 the two diseases were one and the same, 

 but for the following reasons: in yellow 

 fever there is no change in the number of 

 red blood corpuscles; whereas, in malaria 

 there is great change. In malaria the 

 fibrin seems all right as to coagulative 

 properties; in yellow fever the fibrin of 

 the blood loses that important charac- 

 teristic. 



To get back to the sestivo-autumnal para- 

 site : What does it look like 1 Where and 

 how does it develop ? Where does it come 

 from? How did it get into the blood? 

 With a one-twelfth oil immersion lens, the 

 best working objective for blood work, we 

 see in a red corpuscle in the first stage a 

 very small ring-like refractive body which 

 gradually gets larger and larger until the 

 pigment is formed and the corpuscle is 

 somewhat shunken or crenated. The pig- 

 ment increases preceding segmentation of 

 the parasite and the formation of crescents 

 and also before the escape of the parasite 

 from the red blood cells and the throwing 

 off of the flagella. The flagellse enter other 

 blood corpuscles and repeat the cycle of de- 

 velopment, unless destroyed by the white 

 blood corpuscles or by some anti-toxin 

 or anti-malarial drug such as quinine or 

 arsenic in the blood serum. Where this 

 parasite comes from is hard to say. How, 

 when or where the first case originated is 

 still one of the mysteries of nature. 

 How does the parasite get into the blood? 

 This is now well understood. It is 

 through the agency of the Anopheles mos- 

 quito, and in all probability the Anopheles 

 crucians, as the prevalence of this fever 



corresponds quite well with the flight and 

 distribution of that mosquito. I would 

 not consider this the only host for this 

 parasite. Let us consider all mosquitoes 

 as guilty, and destroy them at least for 

 sanitary purposes. It is well known now 

 that the mosquito bites an infected indi- 

 vidual and the infected blood is taken into 

 the stomach of the mosquito, there the 

 blood is digested and the micro-organisms 

 after going through certain changes, which 

 are quite well known, form spindle-shaped 

 objects which perforate the stomach walls. 

 These are the zygocytes which go through 

 different changes and finally get into the 

 salivary glands of the mosquito, and are 

 injected into the tissues of man's body, 

 then in going through other series of 

 changes produce the malarial parasite 

 which we see in the blood of persons suf- 

 fering from malarial fever. The various 

 changes which take place in these bodies is 

 quite well known, and almost any text- 

 book on medicine describes the whole proc- 

 ess minutely. 



Period of Incubation. — It is not defi- 

 nitely known for this fever. 



Clinical History.— This disease is usually 

 ushered in with a chill of greater or less 

 severity. The fever rises rapidly to 102° 

 P., and as high a,s 105° F., even higher in 

 bad cases. The pulse varies in different 

 individuals from 100 to 160 per minute, 

 and varies in various stages of the disease 

 and condition of the patient. I have seen 

 it as low as 40 per minute. Nausea, 

 violent headache, backache and pains in the 

 limbs usher in the disease. The fever usu- 

 ally declines at the end of ten hours and 

 gradually disappears, possibly to return, 

 or perhaps cured by nature or medication. 

 If the infection is great or the patient is 

 not taken care of, the fever assumes a 

 more continuous character and many cases 

 go into a state of collapse after a few 

 days ; the pulse in this case is slow and the 



