230 On the Preservation of Teleostean Ova. 



(6) Alcohol 4 parts, 2-per-cent. acetic acid 4 parts, spirits 

 of camphor 1 part. — The results here were very similar to 

 the preceding fluid, but the embryos were not so distinct, 

 owing to the slight opacity of the eggs ; on the other hand, 

 the shrinkage was very little. There are many objections to 

 a picric solution which are here met. For general work or 

 for preserving large collections of ova this is undoubtedly 

 the best preservative I have used. 



Species. Average shrinkage. 



millim. 



Trigla gurnardus "IS?! 



Oadus inorrliua "1295 



aglefinus •1295 



minutus •1143 



Motella mustella ^914 



Brosmius brosme '1143 



Hippoglossus limandoides "1219 



Rhombus Icevis "1143 



Aimoglossus laterna "1219 



Pleiironectes platessa "914 



Clupea sprattus '990 



(7) The following mixtures of Kleinenberg's picro-sulphuric 



acid were tried : — 



Picro-sulpli 1) 21 1 



... ^i _i _ 



Alcohol OV 2\ 2 



2-per-cent. acetic acid . . 3)4 per cent. 2 J 1 



The results in all cases were unsatisfactory. When the 

 two parts of 4-per-cent. acetic were used the ova {Trigla 

 gurnardus) were considerably distended. 



(8) Very satisfactory results were obtained with 50-per-cent. 

 alcohol. The shrinkage was small, the oil-globule, however, 

 was indistinct ; the dense opacity is also a disadvantage. 



(9) Perenyi's fluid stained the eggs a very dark violet. 

 Diluted with 8 parts of 50-per-cent. alcohol very satisfactory 

 results were obtained. The shrinkage averaged "ISTl 

 millim., and the embryo in all the species experimented with 

 showed well. 



"When ova were not permanently required they were 

 allowed to remain in a 2-per-cent. solution of acetic acid, or 

 4 parts of the same to 2 parts alcohol and 1 part Perenyi's 

 fluid ; both mixtures gave good results. When the embryos 

 were well advanced they were allowed to remain in the former 

 medium until considerable distension took place — about one 

 hour or less. No effect was noticed upon the embryo until 

 four or five hours. 



In conclusion, it will be seen that the most satisfactory 

 i-esults were obtained by killing in the picro-hydrochloric 

 acid and preserving in method 6. 



