343 



The Preparation of Serial Sections of Insects, based upon 

 Experiments with the Blow- fly. 



By Brigade-Surgeon J. B. Scriven. 

 {Read June 20th, 1902.) 



As many members of the Quekett Club have asked me about 

 the mode of setting up the preparations I have exhibited from 

 time to time at our meetings, I have thought it worth while to 

 write a short paper on the subject. The matter, however, has 

 been so well treated by Dr. Benjamin Thompson Lowne in his 

 interesting book on "The Anatomy and Morphology of the 

 Blow-fly," * that it will only be necessary for me to touch upon 

 certain points, in which further experience has opened up new 

 knowledge, or suggested improvements on former methods. 

 Dr. Lowne himself was aware of certain defects in his plan of 

 operations; more especially he lamented the immense amount 

 of labour and time they involved, and he implied that future 

 observers would do well to try and simplify them. This object 

 has to some extent been attained in the methods I am now 

 about to describe. Let us consider — 



1. Certain preliminary measures. — An insect is most conve- 

 niently killed by chloroform. The proceedings immediately after- 

 wards differ a little, according to the stage of its existence. 

 A maggot should be boiled for five minutes in water,t and then 

 dropped into methylated spirit. After twenty-four hours in this, 

 it should be cut through, or a slice taken off with a sharp razor, 

 in the direction in which thin sections are to be made. It should 

 then be put into absolute alcohol (to be changed every twenty-four 

 hours) for at least three days. Boiling drives out the air effectually 

 from the maggot, and coagulates its albumen. 



A pupa should likewise be boiled, but slowly : for rapid boiling 

 sometimes bursts the shell and spoils the contained nymph. 

 Boiling, however, does not remove the air so thoroughly as in the 



* Pp. 93-8 and 347-50. 

 t Lowne, p. 94. 



