Making Permanent Microscope Slides of Insects
Posted: Tue May 26, 2020 8:09 pm
Can anyone recommend books or publications on how to make permanent slides of insects , large and small. I have general ideas but would like tried-and-true methods.
About six decades ago I had a book on slide making which has been long misplaced or lost. It was very thorough, right down to the processing of the dark insect exoskeletons with Potassium Hydroxide, dehdration and then using clove oil as a clearing agent.Today I use Xylene. Does anyone know if clove oil is a better clearing agent than xylene because I know that xylene is very toxic ?
I remember the book stating that flattening the insect was accomplished by rolling it with a wooden handle from a dissecting needle. This part was very tricky as it was easy to break off legs, etc.
Today, I flatten the insects between two glass slides carefully squeezing the slides together while observing through a stereo microscope to ensure not over squeezing. To prevent this I use a shim such as a piece of index card. If the insect is very big and very dark, I over-"cook" the insect in Potassium Hydroxide (I make a saturated solution of KOH) and then flatten using two paper shims to double the space between the two slides. I then hold the slides together with small paper clips. The dehydration process is not affected by this small space between the glass slides but to make sure that there is an exchange of water and alcohol with higher concentrations, I dunk the slides in and out of the alcohol several time visually confirming that the alcohol leaves the slide before re-introducing.
There is much more that I do not remember so any professional documentation on insect slide preparation will be much appreciated.
About six decades ago I had a book on slide making which has been long misplaced or lost. It was very thorough, right down to the processing of the dark insect exoskeletons with Potassium Hydroxide, dehdration and then using clove oil as a clearing agent.Today I use Xylene. Does anyone know if clove oil is a better clearing agent than xylene because I know that xylene is very toxic ?
I remember the book stating that flattening the insect was accomplished by rolling it with a wooden handle from a dissecting needle. This part was very tricky as it was easy to break off legs, etc.
Today, I flatten the insects between two glass slides carefully squeezing the slides together while observing through a stereo microscope to ensure not over squeezing. To prevent this I use a shim such as a piece of index card. If the insect is very big and very dark, I over-"cook" the insect in Potassium Hydroxide (I make a saturated solution of KOH) and then flatten using two paper shims to double the space between the two slides. I then hold the slides together with small paper clips. The dehydration process is not affected by this small space between the glass slides but to make sure that there is an exchange of water and alcohol with higher concentrations, I dunk the slides in and out of the alcohol several time visually confirming that the alcohol leaves the slide before re-introducing.
There is much more that I do not remember so any professional documentation on insect slide preparation will be much appreciated.