230 BYRNES. [Vol. XVI. 



sules containing the eggs were then washed in water and were 

 afterwards passed through the various alcohols. Preparatory 

 to imbedding the egg in paraffine, most of the capsule was cut 

 away, only that part being left which immediately surrounds 

 the Qgg. After using this method of preparation it was found 

 to be almost impossible to section the eggs, owing to the ex- 

 treme brittleness of the hardened jelly around them, so that 

 although the eggs themselves seemed well preserved, the 

 method had to be abandoned as impracticable. It was found 

 necessary to resort to the tedious method of removing the eggs 

 one at a time from the capsules. This was done as follows : 

 Each egg was watched under the microscope until it had 

 reached the desired stage of development ; the capsule was 

 then quickly placed in a saturated solution of corrosive subli- 

 mate, to which 5 per cent glacial acetic acid had been added. 

 As soon as the Qgg had become white and opaque, the capsule 

 was removed to a bath of distilled water. The capsules were 

 then opened under water, and the eggs were returned, free 

 from the jelly, to the corrosive sublimate acetic solution, where 

 they were allowed to remain for a few minutes. They were 

 then passed through the alcohols (35, 50, and 70 per cent suc- 

 cessively), and finally into 90 per cent alcohol, where they were 

 kept until used. 



By far the best results, however, were obtained from eggs 

 that were fixed for from 15 to 20 minutes in Flemming's 

 weak solution, after they had been killed in corrosive sublimate 

 acetic solution. This method is always [uniformly] successful, 

 and the preparations made by it show the minutest details of 

 structure. 



A few good preparations were also obtained by the use 

 of picro-acetic acid, 2 per cent, as a fixative after corrosive 

 sublimate acetic. This method was, however, generally unsatis- 

 factory, as the picric acid often completely destroyed the struc- 

 ture of the centrosphere. The great advantage of corrosive 

 sublimate acetic over other killing reagents is that it pene- 

 trates the capsule very quickly without hardening it. If the 

 corrosive sublimate acetic solution be allowed to act too long 

 on the capsules, so that the inner layers become toughened, 



