

MEDICINE, RECENT ADVANCES IN. 



343 



-on foot, and his average pay is $120 a year. In 

 Belgium the rural carrier makes a daily round 

 trip of 15 or 10 miles on foot. His salary varies 

 with the supposed cost of living- in the district he 

 serves. It never exceeds $250 a year. He is de- 

 nied the right to vote, and is prohibited from tak- 

 ing part in politics. 



MAINE. (See under UNITED STATES.) 

 MARYLAND. (See under UNITED STATES.) 

 MASSACHUSETTS. (See under UNITED 



iSTATES.) 



MEDICINE, RECENT ADVANCES IN. 



Malaria and Mosquitoes. It has been proved 

 that the puncture of a certain species of mosquito, 

 the Anopheles, is capable of causing malaria, and 

 it is now believed by many students that this is 

 the only way in which malaria can be contracted. 

 In practical importance the discovery ranks next 

 to Lister's antisepsis, and it will be one of the 

 historical achievements of nineteenth-century 

 medicine. The history of the gradual unraveling 

 of the complicated scheme in which the malaria 

 germ, man, and the mosquito are used for the 

 continuance and spread of the disease is, as Dr. 

 Manson has happily put it, one of the true fairy- 

 tales of science. In order to follow the theory, it 

 is simply necessary to remember that healthy 

 human blood consists of a fluid portion, the blood 

 plasma or liquor sanguinis, and a solid portion 

 made up of twt> forms of cells, or corpuscles as 

 they are usually called. The red corpuscles are 

 round, disk-shaped, reddish bodies containing the 

 hemoglobin, which gives the blood its color and 

 its efficiency as a sort of vital dumb-waiter for the 

 tissues. The white corpuscles or leucocytes are 

 larger than the red ones, and are spherical. 



The complete life cycle of the malaria germ, 

 which is not a bacterium but an animal, belong- 

 ing to the lowest group of the animal kingdom, 

 the protozoa, forms a closed circle through man 

 ;and the mosquito, so its life history may be taken 

 up at whatever point is most convenient. Let us 

 assume, then, that we have a man with a well- 

 marked case of malaria chills, fever, chills, fever, 

 ad inftnitum. If we examine this man's blood we 

 shall find in a number of the red corpuscles a 

 small, pigmented, jelly-like mass. This is the ma- 

 laria germ. It grows by eating the substance of 

 the corpuscle, just as a mouse would eat the 

 inside of a cheese. Each germ finally develops 

 into a little patch of protoplasmic mosaic, by 

 dividing its body into minute pieces called spores, 

 and then breaks up, and the pieces wander off 

 in the blood stream. Some of them attack other 

 corpuscles and set themselves up as new mother- 

 germs, which in their turn grow and produce 

 infant hcemamoebidce (this is the scientific name of 

 the malaria parasite), and others are eaten by 

 the phagocytes, the scavengers and police of the 

 blood. 



But always some of the original germs, al- 

 though they grow as do the others, by eating the 

 substance of the corpuscles in which they lie, 

 never separate into spores, but remain as simple 

 large homogeneous masses. A hungry mosquito 

 comes along and takes a drink of the man's 

 blood. The result is that she extracts, along with 

 the blood, some of these germs which have not 

 divided, and which have no function as long as 

 they remain in the human body. But as soon as 

 they enter the mosquito's stomach they become 

 active, and undergo a series of changes and com- 

 binations quite different from those that occurred 

 in their brothers in the man's body. This finally 

 leads to the production of great numbers of small 

 needle- or spindle-like organisms in the stomach 

 of the mosquito. And now comes perhaps 



ilt,] 



the most remarkable part of 1h. 

 These little germ rods, us they ;i; 

 pear as soon as they are hutched 

 of the mosquito, and arc next 

 in various nooks and corriei> 

 mosquito's proboscis. And when tin 

 punctures her next victim sonic of the 

 rods escape into his blood. Here; they \\> 

 another transformation, and soon aftenvu 

 velop into the typical malaria parasite 

 which we started. 



So far as is now known, the only way in which 

 a mosquito can obtain malaria germs is by suck- 

 ing blood from a malarial sufferer. And the only 

 way a man can contract malaria is through the 

 injection of the germ into his blood by the mos- 

 quito. That is to say, not only are both man and 

 the mosquito necessary for the production of 

 malaria, but they must be brought together. The 

 life cycle of the germ is, Man A to mosquito A; 

 mosquito A to man B; man B to mosquito B; 

 mosquito B to man C, and so on. 



To trace out and prove this complicated 

 scheme, to locate the germ and convict the car- 

 rier of it, has required about twenty-five years 

 of constant work by numerous investigators. The 

 malaria parasite itself was undoubtedly seen more 

 than seventy years ago by Meckel, who in 1830 

 described certain black particles he had seen in 

 white blood-corpuscles, and also in other ameba- 

 like bodies that were not apparently normal con- 

 stituents of the blood. He had no idea, however, 

 what these bodies were, except that he recognized 

 the pigment as of malarial origin. Some years 

 later his observations were repeated by Frerichs 

 and Virchow, who also failed to recognize the 

 true significance of their discovery. 



Early in the autumn of 1880 Laveran, a French 

 army surgeon stationed in Algiers, again came 

 across these pigmented bodies in the blood of 

 a malaria patient which he was examining. He 

 naturally wondered what they were, and whether 

 they had any connection with the malaria from 

 which he knew the man to be suffering, and he 

 determined to study them. He was soon led to 

 suspect that they were living organisms (he saw 

 them move and even grow), and finally was able 

 to prove to his own satisfaction that they were 

 the real parasites that caused malaria. He an- 

 nounced his discovery to the French Academy on 

 Nov. 23, 1880: " J'eus a.ce moment meme 1'intui- 

 tion que j'etais en presence de veritables microbes 

 du paludisme, et tous les faits que j'ai observes 

 depuis lors n'ont fait que confirmer cette impres- 

 sion premiere." He observed and described some 

 of the curious changes that the parasite under- 

 goes as it eats out the inside of the red blood-cell 

 in which it lies. He saw the rosette and flagel- 

 lated bodies, as well as the strange crescents, 

 which we now know play so important a part in 

 the transference of one form of the disease. He 

 saw a medley of things, but they were so strange 

 and apparently unrelated that he was not able 

 to put the various appearances together and 

 prove the unity of the different forms. As Dr. 

 Manson has said: "He had plunged into what 

 was then almost a new zoological kingdom, and 

 it was little wonder that he did not recognize the 

 relationship to each other of the different items, 

 so to speak, that composed the strange fauna. 

 It was as if some intelligent being from the 

 planet Mars, unacquainted with our fauna, had 

 dropped into this world and had come across 

 some such zoological collection as the inhabit- 

 ants of a fowl-run. He would see fowls, and 

 feathers, and eggs, and empty egg-shells, etc. But 

 he would not be able for a long time to recog- 



