142 



POPULAR SCIENCE MONTHLY. 



races are specifically different. The [ cicadas in the United States, seven of 

 late Prof. Charles V. Riley distin- which appertain to the thirteen-year 

 guished twenty-two different broods of J period [Cicada tredecem). 



MINOK PARAGRAPHS. 



The Bureau of Nature Study of 

 Cornell University is making a praise- 

 worthy effort to interest children in 

 caring for birds, or, as its circular has it, 

 treating them as " summer boarders." 

 It publishes a leaflet entitled The Birds 

 and I, which it sends free to teachers 

 who ask for it and who will give it to 

 their pupils. It has pictures of various 

 styles of bird houses, which may serve 

 as patterns for the construction of 

 homes for the summer guests. " The 

 kind of birds," the interesting circular 

 of the bureau says, " that will set up 

 housekeeping in the homes that you 

 provide will harm no one. They are 

 never cross, never throw stones or rob 

 us, but are always happy and have 

 cheerful songs. We are always kind to 

 people having such dispositions, and 

 why should W'e not be so to birds as 

 well?" The bureau invites correspond- 

 ence from boys and girls disposed to 

 entertain birds. 



The National Geographic Society 

 offers prizes of one hundred and fifty 

 dollars and seventy-five dollars several- 

 ly for the first and second best essays 

 relating to pre-Columbian discoveries 

 and settlements of the Norsemen on the 

 mainland of North America, and the 

 location of the lands mentioned in the 

 Icelandic Sagas, the competition to 

 close December 31, 1899. The essays 

 sent in should be typewritten in the 

 English language, not exceeding six 

 thousand words in length, and may be 

 accompanied by maps and illustrations 

 for explanation of the text, but not for 

 embellishment. The committee of 

 awards consists of Mr. Henry Gannett, 

 Prof. Albert Bushnell Hart, Mrs. Anita 

 Newcomb McGee, Prof. John Bach Mc- 

 Master, and Coast Survey Superintend- 

 ent Henry S. Pritchet. 



Experiments by a German natural- 

 ist, Herr Albrecht ]3ethe, summarized in 

 the Revue Scicntifirjue, upon recognition 

 of one another by ants, confirm the 

 opinions of Lubbock, McCook, Forel, 

 and others that they are guided by the 

 sense of smell. Herr Bethe found that 



an ant " whitewashed " with liquid of 

 ants of its own nest was well received 

 by its fellows when it went among 

 them ; but when the liquid of ants of 

 a different nest was applied it was at- 

 tacked at once. An ant washed with 

 alcohol, next with water, and then with 

 the liquid of a strange species was well 

 received in a nest of that species, al- 

 though it was much smaller than any 

 of the individuals composing it. An- 

 other ant washed with alcohol and 

 water, dried, and immediately returned 

 to its fellows of its own nest, was at- 

 tacked by them; but when kept for 

 twenty-four hours after drying, or long 

 enough to recruit itself, was received 

 by them. 



The following tables are taken from 

 a paper by Dr. J. Richardson Armstrong 

 in a recent Lancet, describing his ex- 

 perience with diphtheria antitoxine in 

 private practice in treating one hun- 

 dred and twenty-two cases of diph- 

 theria : 



In answer to the question, Should 

 every case of diphtheria be treated 

 with antitoxine, Dr. Armstrong says: 

 " Some of the cases are sufiiciently 

 mild not to need it, so I will not go so 

 far as to say that it is absolutly essen- 

 tial to inject in every case, although 

 I would call it an excellent practice to 



