32 JOURNAL OF THE [January, 



any certain results, such dissections must be made as soon as 

 possible after their death, because the character of the internal 

 organs, especially of the muscle and nerve-fibres, changes very 

 quickly when the life is extinct. The best plan is to bring the 

 insect home alive, kill it in the cyanide bottle, and dissect it 

 immediately. 



The slides here exhibited were made, unfortunately, from 

 beetles that had been dead some three days before I could get 

 the time to work upon them. Consequently the preparations 

 do not present the same appearance that they would have, were 

 they made from insects recently killed. They are simple labor- 

 atory mounts, and are not finished, nor are they intended for 

 the cabinet. 



Correction of the Article, " Raising Diatoms in the 

 Laboratory." — The following correction of a slight error in 

 the Article, " Raising Diatoms in the Laboratory," published in 

 this Journal, Vol. IL, p. 153, has been received from Dr. 

 Lockwood: 



"There is a little discrepancy in my Paper on ' Raising Dia- 

 toms in the Laboratory,' read before the New- York Microscop- 

 ical Society, December 17th, 1886, and published in the Jour- 

 nal of the same. Referring, on page 7, to the first series of ex- 

 periments, they are made to extend 'a little over two years.' 

 This should read, ' a little over one year.' The actual time was 

 nearly fourteen months, as the context plainly shows." — S. 

 LocKwooD, Freehold, N. J., October i8th, 1887. 



