382 OOKINESIS IN LIMAX MAXIMUS. 



the best satisfaction was as follows : — The body cavity of a laying 

 animal was opened with a quick cut of the scissors, and the animal 

 plunged into a boiling hot solution of corrosive sublimate; allowed 

 to remain one minute ; transferred to water, and eggs removed 

 from oviduct and shelled/'^' Vitellus allowed to remain in distilled 

 water two minutes, then transferred to 35 and 50 per cent, alcohol, 

 remaining three mintes in each grade; then to 70 per cent, alcohol 

 for permanent preservation. I found that if eggs were allowed to 

 remain in distilled water three hours or more, they shelled better, 

 the vitellus coming out clearer and freer. For examination ofeggs 

 in toto^ Czokor's alum cochineal gave, as a rule, good results. Ten 

 minutes' stay in this dye appeared to give the necessary differenti- 

 ation ; but for examination of sections much longer time was 

 necessary, two to three hours or more. Picrocarminate of lithium 

 was also found to be excellent, if anything, better than Czokor, on 

 account of its differentiating nucleus structures. For examination 

 in toto, twenty-four hours in this stain, and then washing with 

 distilled water and pure alcohol, gave good results. 



Section staining on slide was also found desirable, and Safranin 

 was the stain used — two and a half hours, followed by acidulated 

 (I per cent. HCl) alcohol of 90 per cent, grade for seven to ten 

 minutes. The Schallibaum should be new, the sections carefully 

 applied to a well-smeared slide, and kept at 60° C. for exactly 

 fifteen minutes. If Mayer's albumen fixative is used, only warm, 

 and as soon as paraffine is melted remove slide from heat. 



A number of sections of the hermaphrodite duct {k.d., Fig. i) 

 were made. One egg was found, in this duct, near the hermaph- 

 rodite gland, containing two polar corpuscles, each surrounded with 

 a faintly stained Hof, and each showing striae radiating from cor- 

 puscle through Hof. About eight chromosomes were observed 

 irregularly grouped in the well-defined archoplasm of Boveri.t 



From these sections it appears that the centres of attraction 



* In the upper part of the glandular portion of the oviduct there were a 

 number of eggs in which the outer membrane or shell was barely formed ; in 

 some, egg No. i for example, there was no membrane at all, and in others only 

 the inner membranous coat was present. 



t Zellen-Studen von Dr. Theodor Boveri, Jena, 1887. 



