1894.] 37 



G-EEASE. 



I read Dr. Knaggs' article on grease in the last number of the Magazine -with 

 considerable interest. Some four or five years ago I investigated the subject with a 

 view to finding a satisfactory method of preventing its formation, mostly by means 

 of antiseptic and other injections, but with no success. I now adopt a method of 

 removing it very similar to that of Dr. Knaggs, using ether. It is, however, not 

 with its prevention but with its formation that I am now concerned. 



Dr. Knaggs seems to have overlooked the fact that grease is the result of death, 

 a product of putrefaction. Fat in the recent state consists of cells with proteid walls 

 and fatty contents bound together by connective tissue. As a result of putrefaction 

 the cell walls break down, and the fatty contents are liberated ; moreover, the fat 

 itself is disorganized to some extent, it is more fluid and oily than when recent, in 

 fact, rancid, and it is in a most suitable form for permeating the tissues. In this 

 way our insects become greasy. 



Dr. Knaggs has also advanced a theory to account for males becoming greasy 

 more readily than females, and asserts that males require more energy than females. 

 That a male insect, with its light body and its insignificant share in procreation, 

 should require and acquire more vital energy than the heavy bodied female, with all 

 the duties of maternity before her, seems indefensible at first sight. In fact, all our 

 modern theories and collected facts directly contradict it. Greddes and Thompson* 

 have thoroughly threshed the matter out, so I need write no more about it. The 

 real reason is, I think, that the oviducts with their contents take up such a lot of 

 room in the abdomen of the female, that her abdominal fat becomes almost nil, and 

 that, therefore, her chances of becoming greasy are relatively smaller. 



Now with regard to internal feeders. Some people tend to lay on fat by reason 

 of their employment and habits, so do the internal feeders lay on more fat by reason 

 of their habits, and having done so are more liable to grease. 



When a Frenchman wants to fatten up a capon he puts it in a dark room. 

 Now an internal feeder lives all its life in a dark room, moreover, it takes very little 

 exercise ; its food contains more carbo-hydrates than that of an external feeder, and 

 carbo-hydrates are the only sources of fat, with very few exceptions, for caterpillars ; 

 and lastly, it uses up none of its energy to lay on pigment or to grow bristles or other 

 appendages for protective purposes. No wonder, then, that it grows fatter than its 

 less favoured brethren. 



The great prophylactic against grease is of course drought. With the exception 

 of the most inveterate, my insects seldom grease, and disarticulation by verdigris is 

 a rarity among my Micros, although I use gilt pins, which I believe have a bad 

 name in connection with verdigris. I am, however, most scrupulously careful about 

 keeping the room in which the insects are as dry as possible, and I find a piece 

 of seaweed of great use as a tell tale. — Richaed Feeee, Rugeley, Staffordshire : 

 January, 1894. 



Lepidoptera of Cornwall. — I am compiling for publication in the Transactions 

 of the Penzance Natural History and Antiquarian Society a List of Cornish 

 Lepidoptera, and shall be glad of information from entomologists who may have 

 recently collected in the County. — W. E. Baily, Forth Enys Museum, Paul, near 

 Penzance : January, 1894. 



Evolution of Sox. Contemporary Science Series, 1889. 



