612 



THE AMERICAN NATURALIST [Vol. XL 



111 the course of this work several fixing reagents have been 

 tried with varying degrees of success. ( )f tliese, Kleinenberg's 

 picrosulphuric mixture has proved entirely satisfactory in most 

 cases, but the best results have been obtained from the fluid 

 used by Cameron and known as the Bles fluid; it is made as 

 follows:— 



The cnd)rv(.s remained in this for one week and were then trans- 

 ferred to TO' , alcohol. 



When needed, the eyes were dissected out, cut in halves by a 

 vertical section through the optical axis, and placed in 90 % alco- 

 hol for three hours, followed by 95 % alcohol for from six to twelve 

 hours according to size. They were then cleared in cedar oil and 

 finally imbedded in paraffin, being passed through two paraffin 

 baths of one and three hours each, kept at a temperature of 53° C. 



All -sections were made with a Bausch and I.omb sliding micro- 

 tome and mounted in the usual way. All were stain(vl on the 

 slide. 



