46 THE AMERICAN MONTHLY [February, 



have not heard of it in latitudes north of the fortieth degree, nor does it 

 seem to thrive in the far West. 



Many correspondents have confirmed my statement that chiggers are 

 partial to blackberry bushes. Attention has also been called to the fact 

 that the insects have a special liking for peach trees. 



The chigger does not confine itself to a strictly human diet, but at- 

 tacks the house fly {inusca domestica) . I have not personally observed 

 the parasite on flies, but Dr. G. De Von informs me that he has. He 

 thus accounts for the transportation of chiggers to infants that do not 

 come in contact with living vegetation. 



Dr. J. T. Whitlock finds that chiggers are also very troublesome to 

 young fowls, especially small chickens. He has observed the parasites 

 collected in lumps as large as the head of a pin, and has seen as many 

 as a dozen such lumps on one chicken not two weeks old. He further 

 states that in such cases the chick generally dies promptly, with all the 

 symptoms of poisoning by strychnine. He reports the case of a chick 

 dying after a number of tetanic spasms, lasting for perhaps an hour. 



There is a great difference in the degree of susceptibility of different 

 persons to these parasites. Several persons have assured me that they 

 are never attacked by chiggers, bed-bugs, fleas, or ticks. On the other 

 hand, one of the most prominent microscopists of this age writes that 

 his daughter is so severely afflicted by chiggers that she has been con- 

 fined to her bed for several days. 



Some specimens of the insect are almost transparent, but they all be- 

 come darker in color as they engorge with blood. 



I find that both keresene and spirit of camphor are extensively em- 

 ployed to prevent the attacks of the parasite, and to cure sores when 

 formed. 



San Francisco Microscopical Society. — W. E. Loy, Sec'y. 



Wednesday, Dece??iber J ^ i8gi. — In the absence of the President, 

 Vice-President J. G. Clark occupied the chair. The Secretary reported 

 the usual accessions of scientific periodicals, and as donations a volume 

 on " Disinfectants," prepared for the National Board of Health by Dr. 

 Sternberg (donated by the author) , and a valuable report made to the 

 Secretary of Agriculture on " The Parasites of vSheep," by Dr. Cooper 

 Curtice, connected with the Bureau of Animal Industry. 



There being no regular paper before the society, Charles W. Smiley, 

 editor and proprietor of the A?nerican ^Monthly Microscopical Jour- 

 nal, Washington, addressed the meeting, giving an account of the vari- 

 ous scientific bodies in Washington, and mentioning incidentally the 

 work being done by the different specialists in or near that city. He 

 maintained that the most important invention in aid of microscopical 

 research, after the instrument itself, was the microtome. By its aid 

 students in animal and vegetable histology were enabled to make a com- 

 parative study of tissues not possible without it. He thought the next 

 most desirable aid would be a rapid and cheap method of mounting 

 sections, so that the student could quickly prepare an entire series of 

 sections. Mr. Smiley also spoke of the periodical literature of the 

 microscope, as developed in the United States, and regretted that with 

 a population of 63,000,000 an edition of i ,500 copies served those inter- 



