( 785 ) 



XIV. — On an Improved Method of Freparing Enibryological and 

 other Delicate Organisms for Mieroscopical Examination. 



By Edwaed Lovett. 



iRead 10th October, 1883.) 



During the progress of microscopical science, that department 

 which relates to the preparation, either temporarily or permanently, 

 of the various objects required for investigation has naturally 

 received a very large share of attention ; whilst some workers 

 have devoted the whole of their time and attention to the careful 

 study of this or that particular branch of natural history, others 

 have on their part been the means of bringing the Microscope and 

 its apparatus to its present high state of perfection, whilst others 

 again have sought out the best method for preparing and pre- 

 serving the countless subjects of microscopical examination. 



It is more particularly to the latter branch that my paper 

 refers, although the process which I shall describe was merely the 

 result of a strong desire on my part to preserve the beautiful forms 

 I so constantly met with during my study of the Stalk-eyed 

 Crustacea of the English Channel. 



The methods of permanent preparation for the Microscope 

 have until recently been unsatisfactory, except for certain objects, 

 namely, sections and specimens having no thickness ; but the old 

 system of mounting whole insects crushed, flattened, bleached and 

 contorted was calculated to lead to error upon error, and it is 

 fortunate that a general wish to mount " without pressure " is 

 rapidly being carried into effect, not only in Canada balsam, but 

 also in various fluids. For minute examination of parts, however, 

 with high powers, the flattened method is of course necessary, 

 though very misleading for general outline, structure, and form. 



There are many objects to which Canada balsam could not be 

 apphed, and which owing to their great delicacy would never dry 

 for the purpose of being examined as opaque objects, simply 

 because an attempt to dry them would result in their almost 

 complete disappearance, their structure being supported, so to speak, 

 by the water in which they existed. 



I refer to the delicate organisms of our seas and more especially 

 to their embryological stage, which renders them still more delicate 

 and fragile. 



On the 27th of April, 1877, I collected in Mounts Bay, Corn- 

 wall, some egg-capsules of a mollusc Nassa reticulata, these I 

 placed direct into Haentsche's fluid and mounted in a sunk cell, 

 using marine glue as a cement and finishing with asphaltum and 

 zinc white. 



