METHODS OF STUDYING THE ANNELIDA. 305 
bantlings which have succumbed from want of nourishment. 
We have no intention, however, of allowing the thing to col- 
lapse after so short a trial of existence, and thus we enter with 
confidence upon. our second year, and will carry the undertaking 
through to the end of it. If by that time our prospects have 
not improved, we shall be justified in concluding that the journal, 
has been premature in its arrival. Meanwhile, we would call 
upon all who wish to keep this publication afloat, to use their 
influence in extendingits circulation. 
ON METHODS OF STUDYING THE ANNELIDA. 
oe 
BY WILLIAM A. HASWELL, M.A., B.SC., EDIN. 
Demonstrator of Comparative Anatomy and Physiology, University of Sydney. 
<>— 
Many of the most important observations on the structure of 
the Annelida can only be made on the living or recently-killed 
animal. Such observations must be carried out by the ordinary 
methods of compression and of dissection under water, with the 
aid of the dissecting microscope. But for the demonstration of 
many points in the structure a process of hardening and section- 
cutting must be resorted to. 
Of hardening agents for the Annelida I have found chromic 
acid and corrosive sublimate, followed in either case by alcohol, 
to give the best results. The chromic acid should be used ina 
‘25 / solution. The Annelide should first be killed ina 1% solu- 
tion, but should be removed as soon as dead, after being as far 
as possible straightened, to the weaker solution, in which it may 
be allowed to remain about three weeks. It should then be 
washed in water and placed in rectified spirit for a week, and 
finally in absolute alcohol for a day or two. The corrosive sub- 
limate should be employed in the form of a concentrated aqueous 
solution. After remaining in this for half-an-hour to an hour, 
the animal should be placed in weak (50 %/) alcohol, in which it 
should remain-for 24 hours. It should then be transferred to 70 
7, alcohol for 24 hours more, then placed in strong rectified spirit 
for two or three days, and finally in absolute alcohol for two or 
three days more. 
It will in many cases be found desirable to make two series 
of sections, viz—sections of the animal as a whole, and sections 
of individual organs. Before making the former series it will be 
found desirable to stain the animal as a whole before cutting, 
to avoid the risk of disarranging the sections involved in staining 
them separately. This can best be effected by cochineal, by 
haematoxylin, by diluted Beale’s carmine fluid, or by borax car- 
mine. The cochineal staining fluid is prepared by soaking 
cochineal in strong spirit for a day or so, drawing off the solution, 
