The Birmingham age-herald., 1909-04-11
FEAR OPENING OF
 PANAMA CANAL Physicians Say it May Spread
 Tropical Diseases TRACE MOSQUITOES TRAIL Detective Work Among Dread Dis eases-Thousand Chinese Ex- amined to Discover Dissem-
 inators of Malaria.


 measures were taken against the depre- dations of the wicked insect and the dan ger of mosquito ailments spreading through the civilized world were told the other day by Sir Patrick Manson in an address before the Authors club in Lon don. The well known scientist declared that unless precautions were taken in time the opening of the Panama canal and the development of Africa would re- suit in a wide extension of tropical dis eases There is no yellow fever in Asia or East Africa, and many islands of the Pacific, as well as continental lands, are free from malaria. Both of these mos quito-b borne diseases are likely to spread to the regions where they are now un- known. A representative of the geological gardens in London told of a novel means of warning on the mosquito by breeding @ fish which devours the eggs of the in- sect This fish Is about an inch long, is ! short-lived, but prolific, and It's presence In enormous numbers in Barbados waters accounts for the freedom of those islands from the buzzing pests.
 Elephantiasis the most hideous of mos- quito-borne diseases, was a mystery that interested Sir Patrick Manson during his residence in Formosa and on the coast of China. He came to the conclusion that 1t was caused by an organism in the blood called filaria-"a microscopic animalcule, | eel-shaped and inoiosed in loose sac or sheath within which it wriggles about in the blood very actively" Sir Patrick | found that In some districts of China the 1 parasites were present in 10 per cent Of 1 the population, while elsewhere 50 per cent I of the people were infected with them. l Since the flaria showed no evidence of growth while in the blood. 1t was inferred 1 to be the young of some other animal, 1 and at last Sir Patrick proved that to be 1 the case along with other scientists. The l parental worm, three or four inches long and of the thickness of fish gut. dwelt in 1 the lymphatic vessels. It did not leave its I retreat, where its presence caused the destructive effects of elephantiasls. The 1 question was how it could pass from one l human being to another. Sir Patrick ar l gued that some insect which sucked hu- l man blood, ingesting the microscopic off, spring of the filaria, must be responsible for the transmission. The most likely in- | sect in the premises was the mosquito. DIssecting Mosquitoes.
 | An odd confirmation of this hypothesis soon occurred. The scientist had trained two Chinese medical students to examine I the blood of 1000 Chinese, SO as to get re- l liable data One student found 1t con- venient to work at night the other in the daytime. The night worker found plenty of filaria in his specimens, the other very few These contrary observations, dic-
 
 night specimens of blood had most flaria because the mosquitoes were busy at night To clinch the theory, Chinaman was hired for a small amount to let him self be attacked liberally by mosquitoes. He was put to bed in netted compart- ment in which a large number of insects had been admitted. In the morning the bood-gorged mosquitoes were captured for dissection.
 q shall not easily forget the first mos quito I dissected," said Dr. Patrick
 Placing the blood the stomach contained under the microscope, I was gratihed to find that, so far from killing the filaria. the digestive juices of the mosquito seemed to have stimulated 1t to fresh ac- tivity. And now I saw a curious thing. The little sac or bag inclosing the filaria, which hitherto had muzzled it and pre- vented 1t from penetrating the walls of the blood vessels in the human body, was broken through and discarded. ultimate ly succeeded in tracing the filaria through the stomach wall into the abdominal cav ity, and then into the thoracic muscles of the mosquito. More than that, I ascer- tained that during this passage the little parasite increased enormously in size. From measuring about .01 of an inch in length it grew to about 1-16 of an inch, and was now just visible to the naked eye. It developed mouth, an alimen- tary canal and other organs. Manifestly 1t was on the road to new human host"
 Lives In Insects Head.
 Later on microscopic sections of infect ed insects made in London, clearly dem onstrated that the flaria. after 1t leaves the stomach and reaches the thoracic muscles of the mosquito. continues It's journey toward the proboscis; that for a time 1t lies in the head of the insect; that then it creeps down the labrium or sheath of the proboscis, where, in proper 1y prepared sections, 1t car oe seen lying outstretched and evidently waiting an op- portunity to escape. This opportunity doubtless occurs when the mosquito next proceeds to feed on the human subject. The sections prepared from the skin which the mosquito actually in situ dis play the flaria in the act of passing through the probosofs of the mosquito and actually entering the body through the little hole made by the biting parts of the mosquitoes proboscis.
 Becoming interested afterward in the study of the malaria parasite, and believ- ing the mosquito to be guilty of transmit ting this disease also, Sir Patrick Man son was unable to carry on personal in- vestigation and suggested the subject to Prof. Ronald Ross. The latter, on his re- turn to India. took up the study, and lacking human subjects investigated the malaria of birds. He demonstrated clear ly that the malaria parasite went from bird to mosquito, and back from mosquito to bird. It seemed unnecessary to carry this proof direct to human beings, yet people were skeptical.
 Immune in Campagna.
 Sir Patrick obtained grant of money from the British colonial office to clinch the case He sent from London two or three healthy individuals to the notorious ly malarious region of the Roman cam pagna, and guaranteed that they would not contract the fever with which all tho inhabitants were afflicted, since they would be housed in mosquito-proof cot tages and would not go out after sunset, when the insects abound. At the same time Roman mosquitoes that had fed on Inalarious patients were sent by mall to London and were allowed to bite persons who were never troubled with the dis ease and the scientists announced that these persons would surely develop ma laria. The double experiment was suc- cessful and conclusive. The Englishmen sent to Italy lived in the fever district for months without getting malaria, while the Londoners bitten by the imported in- sects speedily developed the disease.
 Sir Patrick referred to the newly gained immunity of Havana and the Panama canal zone from yellow fever through the elimination of the mosquito. He feared, however, that the opening of the canal. with It's extension of rapid communication between ports might spread tropical dis-