1882.] 



MICKOSCOPICAL JOURN^AL. 



167 



lula, moving out of the posterior end of 

 its proboscis, which was ruptured. It 

 measured about eight one-hundredths 

 of an inch in length by tvvo one- 

 thousandths of an inch in diameter. 

 Subsequently I determined to ascer- 

 tain the interior dimensions of the 

 suction-tube, or proboscis, of the 

 house-fly, for the purpose of compar- 

 ing it with the diameter of this para- 

 site. Placing a fly which I had as- 

 phyxiated with naphthaline on a glass 

 slide, and securing it on its back by 

 means of thick gum, I was able to 

 measure the parts and observe all the 

 movements of its proboscis, and 

 found its suction-tube to be of suffi- 

 cient diameter to admit of taking up 

 the spores of cryptogams, trichinae, 

 the eggs of anguillula, or even the 

 anguillulse themselves. 



Noticing a violent commotion in 

 the abdomen of the fly thus operated 

 on, I became convinced that- one or 

 more of the anguillulae were present 

 in tlie abdomen, and were the cause 

 of the unusual movements observed. 

 On removing the head of the fly, a 

 lively anguillula was seen moving out 

 from one of the ruptured ends of the 

 CESophagus. The animal v/as quickly 

 secured, and placed under a glass 

 cover in a drop of water, where it ex- 

 hibited very lively eel-like or snake- 

 like motions. Shortly a second ap- 

 peared, when all commotion in the 

 abdomen ceased. 



Of the genus anguillula there are 

 upwards of one hundred known spe- 

 cies. * * * The species I have 

 found in the house-fly exhibits difler- 

 ent internal structures, in some re- 

 spects, from any others that I have 

 yet examined. * * * 



The facts above stated suggested to 

 my mind the importance of institut- 

 ing a series of experiments to ascer- 

 tain whether house-flies might not be 

 carriers and distributers of germinal 

 virus. I have found in the proboscis 

 of a single house-fly thirteen of the 

 animals already mentioned in a per- 

 fectly developed condition, and on 

 the thorax of another I have found 



sixteen living parasites of the genus 

 acarus. •» * * 



To test practically the question 

 whether flies may become the carriers 

 of contagious germs, I instituted a 

 series of experiments. In a glass re- 

 ceiver having a capacity of about five 

 gallons of air, I placed several hun- 

 dred house-flies which had been 

 caught in an ordinary fly-trap. With- 

 in the receiver was placed a quantity 

 of the spores of the red rust 

 of grasses ( Tricholoma). The flies 

 at first did not seem to esteem 

 the spores as suitable food, but on the 

 morning of the third day I found 

 that the rust was replaced by larvae 

 and remains of eggs of the common 

 house-fly. 



The eggs were deposited and 

 hatched between Saturday noon and 

 the following Monday morning, 

 9 o'clock, or in about forty-eight 

 hours. On the following day I placed 

 in the receiver about a quarter of an 

 ounce of the same description of 

 spores combined with sugar. The flies 

 partook of this confection, consum- 

 ing the sugar and most of the spores. 

 In about twenty-four hours after 

 the flies had partaken of this mix- 

 ture I killed and dissected a number 

 of them, and found the small intes- 

 tines intensely colored, of a deep red- 

 dish orange shade, representing the 

 digested spores of tricholoma. I ob- 

 served in the contents a few well- 

 defined orange spores, but none of 

 them appeared to have germinated. 

 Fastened between the hairs, on the 

 limbs of each of the flies examined I 

 found a number of the spores, and the 

 efforts of the fly to get rid of them 

 only resulted in attaching them more 

 firmly to it. 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. It 

 was evident from this experiment that 

 flies were capable of conveying such 

 spores to plants and other bodies. 

 On the other hand, the fact that by 

 far the greater part of the spores were 



