136 



THE POPULAR SCIENCE MONTHLY. 



them ; on the other hand, housed vegeta- 

 ble-feeding animals stags, antelopes, oxen, 

 sheep, and goats if reared by hand from 

 birth, become when adult the most danger- 

 ous animals to be met with ; while, if caught 

 after they have grown up, they are timid 

 and fly from man. His experience with all 

 animals of the latter class has been the 

 same as with the lamb, whose case he de- 

 scribes, that was brought up as " one of the 

 family." As it grew larger and stronger, 

 it became self-conscious and independent, 

 having " no fear and less gratitude," and 

 grew so saucy that it had to be consigned to 

 a larsje field, where it became a terror to 

 passers for, " with hop, skip, and ]ump, he 

 was behind any one in an instant ; with one 

 good spring, the unfortunate traveler was 

 on his hands and knees if not on his face " 

 and was finally sentenced to the butcher. 

 Such of these animals as have been bred 

 in captivity (not petted and handled) and 

 reared by the parent, become exceedingly 

 wild if an attempt is made to catch them, 

 pack them up, or move them from one place 

 to another. The reason for these curious 

 manifestations appears to be that the tamed 

 animals, having lost their fear of man and 

 become familiar with him, when the time 

 comes for them to manifest their belligerent 

 propensities, have no respect of persons, 

 and are ready to attack their former friend 

 as they would any other real or imaginary 

 antagonist ; but, when anything new is at- 

 tempted with them, it is as novel as it would 

 be in their natural state, and awakens all 

 their natural wildncss. 



Fnnp;! as Insectkidcs. The possibility 

 of putting a limit to the depredations of nox- 

 ious insects by cultivating the fungi which 

 are destructive to them has been several 

 times suggested. Professor Le Conte recom- 

 mended the study of the epidemic diseases 

 of insects, particularly of the fungoid dis- 

 eases, with this view, in 18*74. Charles II. 

 Peck, State Botanist of New York, advanced 

 a similar idea with reference to the fungi 

 which infest plants, in ISVG, and in 1878 

 described a large destruction of scventeen- 

 year-locusts and of the larvae of insects feed- 

 ing upon the aldor by fungi. Dr. H. A. Ha- 

 gen, of Harvard University, in 1879, thinking 

 he had established the identity of the fungus 



which destroys the house-fly with the yeast- 

 fungus, recommended the use of the latter 

 against noxious insects in general. Pro- 

 fessor A. N. Prentiss, of the Botanical Lab- 

 oratory, instituted a series of experiments 

 during the spring of 1880 with the plants 

 in the laboratory, upon the effects of the 

 yeast-fungus upon the aphides and other 

 insects preying upon them. The record 

 of his experiments is given in the form of 

 a journal in contributions to " The Ameri- 

 can Naturalist." The result of nine experi- 

 ments as a whole, as also of many others 

 not recorded, indicates that yeast can not 

 be regarded as a reliable remedy against 

 such insects as commonly affect plants cul- 

 tivated in greenhouses and dwellings. The 

 attempt to use it is liable to the further 

 objection, that it will be very likely to in- 

 jure many kinds of plants quite as badly as 

 it will the insects. The experiments of Mr. 

 Trelease, of Selma, Alabama, with the yeast 

 upon the cotton-worm, led him to a similar 

 conclusion with reference to its application 

 to that insect. On the other hand, accord- 

 ing to Dr. Hagen, Mr. J. H. Burns, of Shel- 

 ter Island, New York, has had some success 

 with yeast against the Colorado potato bee- 

 tle, and it has been used upon the aphides 

 in a greenhouse in Germany Avith great suc- 

 cess. Professor Prentiss does not consider 

 the question at issue decided by his experi- 

 ments, for the yeast-fungus may be opera- 

 tive on other insects and under other condi- 

 tions than those with which he performed 

 his experiments, and there may be other 

 forms of fungus which, applied with discrimi- 

 nation, would be effective. 



Examination of Germs in tlie Air. Dr. 



Ferdinand Cohn and Dr. Miflet, of Breslau, 

 have been investigating experimentally as 

 to the possibility of detecting the organisms 

 which are regarded as the germs of infec- 

 tion and fermentation in the air in which 

 they are supposed to float. Their experi- 

 ments were carried on from the middle of 

 March to the end of July, 1878, in the air 

 of laboratories, operating-rooms, and the 

 sick-rooms of hospitals ; in the free air of 

 the botanical gardens, and the air gathered 

 at the surface of the soil of the garden ; and 

 in the sewer-air of a court. They found 

 1. That numerous germs exist in the air in 



