P OP ULAB MIS CELL ANY. 



57i 



months ; Yakutsk suffers this mean tem- 

 perature during December and January ; 

 Ustjansk, at the mouth of the Yana, only 

 during January ; while Tolstoi Noos, at the 

 mouth of the Yenisei, lies entirely outside 

 of the isotherm of 40. The mean an- 

 nual temperature of the Siberian cold-pole 

 may be estimated at 2. A still colder place 

 appears to have been found by M. Klut- 

 schak, of Lieutenant Sehwatka's expedition, 

 at the Adelaide Peninsula, in Cockburn Bay, 

 latitude 66 to 68, where the temperature 

 in January, 1880, reached 72 ; in Decem- 

 ber, 1879, and February, 1880, - 68 ; and 

 in September, October, and November, 1S79, 

 5, 3S, and 49" respectively. The 

 mean temperature from December to Feb- 

 ruary, 48, varies but little from that of 

 "Werkojansk, and is from 18 to 21 lower 

 than had been previously noticed in the 

 American cold region. Die Natur. 



Do House-Flies convey Infection ? Dr. 



Thomas Taylor, of Washington, has pub- 

 lished an account of some examinations he 

 has made into the capacity of the common 

 house-fly to transmit disease by carrying the 

 germs from place to place. The question is 

 really one of exceeding importance, for, 

 " considering the habits and habitat of the 

 house-fly, it will appear evident that, should 

 it prove to be a carrier of poisonous bodies, 

 its power to distribute them in human habi- 

 tations is greater than that of any other 

 known insect. Under our system of public 

 travel, the common house-fly may be trans- 

 ported from one end of the continent to the 

 other. It may feast to-day in the markets 

 of Washington, and to-morrow in those of 

 New York, and in a like manner it may be 

 transported from a hospital for contagious 

 or infectious diseases to homes in the vicin- 

 ity, or even in remote localities. It may 

 also be taken from one hospital to another, 

 or from one ward to another within the 

 same hospital, and may plant the germs of 

 disease in exposed wounds, or deposit them 

 in food, or liberate them in the atmosphere 

 breathed by patients afflicted by diseases of 

 a different class." Millions of the minute 

 germs of putrefaction could be carried to a 

 distant city by a single fly. These consid- 

 erations justify and should prompt inquiry. 

 Dr. Taylor's attention was called to the sub- 



ject by his witnessing the sufferings of a 

 fly afflicted with anguilulce. In the direct 

 experiments which were suggested to him 

 by this observation, the larvae of flies con- 

 fined in a receiver with rust-spores ate the 

 germs. When spores were sprinkled on 

 sugar, the insects themselves consumed both 

 spores and sugar ; but some of the spores 

 became fastened on the legs of the flies, 

 and were only the more closely attached by 

 the efforts made to get rid of them. They 

 might, however, be brushed off by objects 

 with which they were brought in contact, 

 while their germinating powers would long 

 outlast the life of the insect itself. Dr. Tay- 

 lor regards it as evident from his experi- 

 ments that flies are capable of conveying 

 spores to plants and other bodies, but con- 

 siders that the fact that the greater part 

 of the spores were consumed by the flics or 

 their larva? shows that the insect may de- 

 stroy microscopic germs as well as dissemi- 

 nate them, and indicates that in some cases 

 its agency in keeping down their number 

 may more than counterbalance its action in 

 contributing to their dissemination. 



American Stature. Mr. George W. Peck- 

 ham, teacher of biology in the Milwaukee 

 High School, has been making investigations 

 under the auspices of the Wisconsin State 

 Board of Health into the growth of children. 

 From examinations and measurements made 

 chiefly in the schools of Milwaukee he has 

 deduced the conclusion that the relative rate 

 of growth of the sexes is such that the boys 

 are taller till the twelfth year and heavier 

 till the thirteenth, after which, between thir- 

 teen and fifteen the girls are both taller and 

 heavier. After the age of fifteen, however, 

 the boys exceed the girls both in weight and 

 stature. Girls cease to grow when about 

 seventeen years of age. Children of pure 

 American descent are taller than children 

 of foreign-born parents, but are generally 

 lighter in weight than children of German 

 parents. The children of Irish parents are 

 also taller than those of German parents. 

 Comparing his results with those of similar 

 observations made in Boston, he concludes 

 that school-children in Milwaukee are taller 

 than those in Boston, and the boys weigh 

 more, but the girls of Boston are slightly 

 heavier than those of Milwaukee. The su- 



