Febeuaey 16, 1900.] 



SCIENCE. 



259 



the active discouragement of his official 

 superiors in India. Thus hampered he 

 was able, nevertheless, to ascertain that a 

 gnat (a culex) is the means of propagating 

 a malaria in birds but not, as it turns out, 

 any one of the malarial parasites of man. 

 At this point the Roman physicians took 

 up the subject, Professor Grassi on the side 

 of zoology. Professor Bignami of pathology, 

 Professor Celli of prevention. Their re- 

 searches have proved, and Major Ross has 

 since verified their statements in West 

 Africa, that malaria in man also is prop- 

 agated by a gnat, but not by a culex ; 

 the enemy of man is a dapple- wiiiged gnat, 

 scientifically known as Anopheles daviger. 

 Professor Grassi showed to his visitors a 

 large number of beautiful drawings illus- 

 trative of the anatomj' of this gnat, and of 

 the life of the parasite within it. The 

 gnat, in sucking the blood of an infected 

 man, takes in the parasite ; this in a spher- 

 oidal form may be demonstrated in the 

 stomach of this fly, and its course, followed 

 closely as it penetrates the walls of the 

 stomach, reaches the juices of the body, 

 as a tiny worm-like creature, and thus 

 wriggles onwards into the salivary (or 

 poison) gland of the insect, whence it is 

 again returned to man by the proboscis. 

 Thus between man and the anopheles these 

 parasites maintain their cycle of life. No 

 man, and no dapple-winged gnat, no ma- 

 laria. 



Not the least interesting part of the visit 

 was the excursion With the professors into 

 the Campagua, where two farms had been 

 selected for experiment. In the one pro- 

 tection was given against the access of the 

 insects ; in the other no such precautions 

 were taken. Other things were equal ; in 

 the former farm was no malaria, in the lat- 

 ter malaria prevailed as beforel Fortu- 

 nately ano2)heles rarely bites men on the 

 move ; secreting itself in their cabins or 

 chambers it attacks them while at rest — 



especially at night, when by certain appa- 

 ratus its inoculations may be avoided. 

 Whether anopheles can be extirpated or not 

 is a large and difficult question. This gnat 

 breeds in pools of a certain kind, not quite 

 stagnant, but supporting confervEe (Limna), 

 on which its larvse subsist. From such 

 pools these larvse were collected and ex- 

 hibited in abundance to the visitors. A 

 small spoonful of common petroleum oil 

 will destroy all the larvte in a square yard 

 of such water, and it seems possible, there- 

 fore, that by drainage, where possible, and the 

 supplementary use of oil the insect might 

 be removed from large areas. In turning 

 up new ground such pools are apt to form 

 and breed the gnat, a result which might 

 be avoided by no very difficult provision. 

 By his generous invitation Commendatore 

 Florio has enabled skilled English observers 

 to verify these invaluable researches — re- 

 searches into the minute habits of very ob- 

 scure creatures which will have neverthe- 

 less a very large effect upon the well-being 

 of man in fertile tracts of the world now 

 too pestiferous for continuous occupation, 

 at any rate, by white men. 



The cure and prevention of tuberculosis 

 has of late years excited the public interest 

 more than of malaria, of which fell disease 

 our home population now happily knows 

 little. From Rome Commendatore Florio's 

 guests were taken to Palermo, and were en- 

 tertained in the Villa Igiea, the exquisite 

 palace, for I can call it no less, in which 

 consumptive patients are to be received and 

 treated on the open air system, with all ad- 

 vantages that a beautiful and uniform cli- 

 mate, a lovely site, and every luxury of 

 life can give. The sanatorium, which will 

 be completed in a few months and then 

 opened by the King and Queen of Italy, is 

 built outside Palermo upon the rocks on 

 which the deep sea of the bay actually 

 beats. In the clefts of these sunny rocks 

 are marble benches, temples and grottoes, 



