1880.] 



MICROSCOPICAL JOURNAL. 



105 



viscera, etc., becomes weakened 

 and unable to move about ; but 

 the viscid fluid extending from 

 the tubular hairs surrounding its 

 pulvilli continues to flow, and the 

 insect becomes glued to the point 

 of attachment, bj the very secre- 

 tion which enables it ordinarily to 

 walk on all surfaces and in all 

 positions. 



People who make a practice of 

 feeding gold fish, etc., with flies, 

 may thus introduce into their aqua- 

 riums a supply of germinative 

 spores^ sufiicient to destroy succes- 

 sive colonies of fishes. Some idea 

 of utilizing this parasite, so antago- 

 nistic to certain forms of animal- 

 life, appear to have been mooted in 

 Am(!rica. The following para- 

 graph, bearing upon our subject, 

 appears in the February number of 

 Science Gossip : 



^^ Parasitic Fungi on Insects. — 

 Professor Hagen, of Harvard, des- 

 cribes some experiments that had 

 been made by Mr. I. H. Burns and 

 others, and comes to the following 

 conclusions : 1. That the common 

 house-fly is often killed by a fungus, 

 and that in epizootics a large num- 

 ber of insects which live in the 

 same locality are killed by the same 

 fungus. 2. That the fungus of the 

 house-fly works as well as yeast 

 for baking and brewing purposes. 



3. That the application of yeast on 

 insects produces in them a fungus 

 which becomes fatal to the insects. 



4. That in the experiment made by 

 Mr. I. H. Burns, all potato beetles, 

 sprinkled with diluted yeast, died 

 from the eighth to the twelfth day, 

 and that the fungus was found in 

 the vessels of the wings." 



Now that the life-history of 8a- 

 jprolegnia ferax has been to some 

 extent examined, we may revert to 

 the causes assigned for its destruc- 

 tive outbreak and extension beyond 

 all previous limits. Mr. A. B. 



Stirling, curator of the Anatomical 

 Museum, Edinburgh, writes as fol- 

 lows : " I also wish to say that the 

 fungus appears to me to be of a 

 very irritating nature, causing the 

 fish such tortures that they destroy 

 themselves in their efforts to get 

 rid of their tormentor. The sores 

 upon the fish are not caused by the 

 fungus, but by the fish themselves 

 by rubbing the parts of their bodies 

 affected, upon stones or rocks and 

 other projections they find to suit 

 the parts affected. I am quite un- 

 able to say what the origin of the 

 fungus may be, but, as I found 

 foreign matter of various kinds, en- 

 tano;led in the mvcelium of the 

 fungi, I have pretty good grounds 

 for thinking that it may have arisen 

 from pollution. The foreign mat- 

 ter found in the mycelium or 

 fronds of the plants, were Torulse 

 or yeast plant, triple phosphates 

 fecula, human hairs, and hairs of 

 cat and mouse ; also, desmids and 

 diatoms, shreds of dyed wool and 

 cotton, with other fragments of 

 matter unknown to me." 



With all due deference to Mr. 

 Stirling, I feel bound to remark, 

 that although the fish in its efforts 

 to get rid of tlie parasite does lace- 

 rate itself, still the skin is already 

 completely disorganized by the 

 growth of the fungus. 



Soft bodied animals, as tad-poles, 

 when attacked are penetrated 

 throughout by the mycelium of S. 

 ferax, and the whole substance of 

 the creature is interwoven with its 

 threads. In addition to the debris 

 detected by Mr. Stirling, other im- 

 purities are detected, as the follow- 

 ing extract from a newsj^aper com- 

 munication well shows : 



" Certain kinds of chemical im- 

 purities are known to be favorable 

 to the growth of fungoid life, and 

 the practice of sheep- washing, which 

 is largely carried out in the rivers 



