April 28, 1922] 



SCIENCE 



447 



At temperatvires below 85 degrees there was 

 very little response if any. 



A comparatively small niim)>er of the mos- 

 quitoes reacted positively to heat at any one 

 time; thus with 300 mosquitoes in the cage per- 

 haps not more than fifteen or twenty would be 

 attempting to feed at the height of the re- 

 action. Whether the same individuals were 

 concerned in each of a series of such responses 

 or whether various individuals at different 

 times took part, was not determined. 



In nearly all of these experiments, which 

 were made in an open insectary, no attempt 

 was made to eliminate the odor of the observer 

 but in some tests made in a closed room in an 

 air-tight apparatus the mosquitoes responded 

 in the usual manner when air was drawn from 

 outdoors through a long tube. It is interest- 

 ing to note, however, that when the breath was 

 bubbled through the water instead of the usual 

 current of air a decided increase of interest on 

 the part of the mosquitoes was manifest. The 

 admixture of various amounts of carbon di- 

 oxide with the air stream did not increase the 

 interest over that shown for undiluted air. 



In one series of experiments a hole about 

 two inches square was cut in the lid of each 

 of two pasteboard boxes which were exactly 

 alike. These holes were covered with cheese- 

 cloth and a layer of absorbent cotton was sup- 

 ported immediately beneath this cloth. In one 

 box the cotton was moistened with cool water 

 while in the other it was moistened with hot 

 water and was supported by a bottle containing 

 hot water. When these two boxes were ex- 

 posed in the mosquito cage considerable num- 

 bers of the mosquitoes would visit the warm 

 box and attempt to feed while they paid no 

 attention to the cool box. 



Several types of traps in which heat was 

 employed as an attraetant wei-e tested in the 

 field and mosquitoes could be caught in even 

 the crudest of these traps but the insects were 

 also able to escape from all of them, display- 

 ing decidedly more ingenuity in this respect 

 than is shown by the house fly. Experiments 

 with more complicated traps were cut short 

 owing to the entire disappearance of mos- 

 quitoes. 



It was also found that mosquitoes in cages 

 fed readily upon a solution of potassium ar- 

 senite in sweetened water and that this material 

 was highly toxic to them. This suggested the 

 use of such a poisoned bait in heat traps and 

 traps were also devised in which the insects 

 might be destroyed upon entering a chamber 

 containing potassium cyanide. Neither of 

 these agencies could be tested in the field. 



S. E. Crumb 

 Btteeau of Entomology, 

 tl. S. Depaetment op Agricultube 



SCIENTIFIC EVENTS 



HEINRICH SUTER 



On March 17 there passed away Heinrich 

 Suter, for many years gj'mnasialprofessor in 

 Zurich, Switzerland, and a noted student of the 

 history of Arabic mathematics and astronomy. 

 For thirty years he was active as a translator 

 and commentator of Arabic authors. The 

 twenty years preceding 1892, when his first 

 distinctly Arabic research was published, were 

 years of preparation, during which he pub- 

 lished a history of the mathematical sciences 

 and a number of papers on mathematics during 

 the Middle Ages in Europe. Most of his 

 shorter articles appeared in the Bibliotheca 

 Mathematica and in Schlomilch's Zeitschrift 

 filr Mathematik und Physik. As regards the 

 quality of Suter's extensive studies of Arabic 

 science it is enough to say that they are highly 

 respected in an age when higher standards of 

 historical accuracy are being established in 

 Europe. 



Suter was born on January 4, 1848, at 

 Hedingen, near Zurich; he studied in Zm-ich 

 and Berlin, and took his doctorate in 1872. 

 Florian Cajoei 



THE CALCUTTA SCHOOL OF TROPICAL 

 MEDICINE 



The British Medical Journal states that the 

 School of Tropical Medicine and Hygiene and 

 the Carmichael Hospital for Tropical Diseases 

 at Calcutta were opened by Lord Ronaldshay, 

 governor of Bengal, on February 4. In the 

 issue of December 3, 1921 (p. 957), it was 

 noted that the School of Tropical Medicine and 



