496 CHARLES W. HARGITT 
collection was absolutely worthless by reason of the almost exclu- 
sive use of this reagent. 
Hermann’s and Flemming’s solutions afforded fairly good fixa- 
tion, but subsequent staining was very difficult. Perenyi’s 
solution was absolutely worthless with both Eudendrium and 
Pennaria material and has since been discarded. ‘The only solu- 
tion which gave reasonably good and fairly constant results was 
a strong solution of corrosive sublimate to which had been added 
5 per cent of glacial acetic acid. 
In later work I made use of various solutions of formaldehyde, 
but with only fair results. A 10 per cent solution in sea-water 
gave a good general fixation for immediate use. Combination 
with corrosive did not seem materially to better it. There was 
found also to be great variability in different species as to this 
matter. This was particularly apparent in eggs heavily yolk 
laden as compared with those in which yolk was lacking, or pres- 
ent in only small quantities. There was also great difference in 
later differentiating other cytoplasmic elements. For example, 
in the peculiar proteid granules present in eggs of Clava the first, 
and only satisfactory reagent was picro-acetic acid (p. 217, 
Biot Bulk, vol,10706); 
In 1906 my attention was directed to Bouin’s picro-acetic- 
formol. It was thoroughly tested upon eggs of Pennaria and 
Hydractinia, and was found to be far superior to any thus far 
employed. I have since used Zenker’s fluid with good results 
in fixation of eggs of several species. It is worth while to empha- 
size the importance of this feature of fixation, especially as it 
relates to coelenterate material. I have called attention to this 
in several previous papers, but it is absolutely imperative in 
order to warrant trustworthy results that particular attention 
be given to this matter. 
3. Imbedding. In another respect I have learned to my cost 
the importance of prompt working up of coelenterate material 
after fixation. Attention was directed to this point in my paper 
on Pennaria (’04b, p. 455). This precaution has been abun- 
dantly confirmed by later experience, and I take occasion here to 
emphasize its importance once more. The value of this has been 
