156 JULIAN S. HUXLEY. 



forget to express my gratitude to Pi-of. Bourne for much 

 kind assistance. 



Methods, etc. 



Preservation. — Some of the Anaspides had been pickled 

 in formalin, some in corrosive sublimate; these latter were 

 much better preserved, and were exclusively used in the 

 work. 



Preparation of the Gregarines. — Mr. Smith's speci- 

 mens of Anaspides had been kept in captivity for some time 

 before they were preserved; and, either they had had very 

 little to eat, or else all the fare provided for them was 

 digestible — at all events their guts were almost empty, save 

 of parasites. Thus it was easy to make preparations of large 

 numbers of the Gregarines by staining the gut and liver- 

 tubes whole in paracarmine for a couple of hours, and then, 

 after taking up to xylol, teasing in Canada balsam on the 

 slide, and removing as much of the debris of the gut as 

 possible, leaving the parasites behind. 



This was quite good for general features, but, as I found 

 to my cost later, did not bring out certain important cyto- 

 plasmic structures. 



Subsequently some more Anaspides were sent over from 

 Tasmania ; these had been preserved at the moment of 

 capture, and their guts were filled with a mass of sand, 

 swallowed for the sake of the contained oi*o-anic fragments. 

 This made matters more difficult. The Ganymedes had to 

 be picked one by one out of the debris by means of a capil- 

 lary pipette under the binocular microscope. They were 

 then mounted from 90 per cent, alcohol on to a film of egg- 

 albumen smeared over a slide, so that they could be stained 

 with Heidenhain's iron hajmatoxylin, which proved much the 

 best reagent for picking out the details of the complicated 

 structures in the cytoplasm. 



Besides making these whole preparations, I had sections 



