134 Proceedings of the Royal Physical Society. 



zoophytes the vitellus never divided ; it became minutely granular and 

 opaque without segmentation. Still, some intermediate form might occur 

 even within the egg. The male of this Lizzia might differ in form or 

 development from the female, as was the case in the medusoids of 

 Atractylis {Eudendrium) ramosa, and Campanularia dichotoma 

 (Loveni). It was well known that although in some zoophytes the re- 

 productive apparatus of the male and female was identical in shape, in 

 others the difference was very remarkable. 



II. Note on an Instantaneous Method of finding Microscopic Objects 

 under High Powers. By T. Strethill Wright, M.D. 



The author stated, that when examining small living organ- 

 isms under pressure, he had frequently much difficulty in 

 placing them under the higher-powered objectives with suffi- 

 cient rapidity. The animals often commenced breaking up 

 before they could be found. By adopting the following 

 method of finding objects, he could instantly, and without even 

 looking through the body of the microscope, place in the centre 

 of the field, and in focus, any object which could be barely 

 detected by the naked eye. 



The fine adjustment slide was marked by a small scratch 

 on the brass-work, and it was afterwards not used. A speck 

 of paper or other substance, sufficiently large to be just per- 

 ceptible to the naked eye, was placed in water on a glass slide, 

 covered with thin glass, placed in the centre of the field, and 

 accurately focussed under the high-powered object-glass. The 

 coarse adjustment was then marked by a scratch on the body 

 of the instrument or the slide of the rack (" scratch No. 1"). 

 The operator then placed the point of his nose on the top of 

 the coarse adjustment screw-head, and the left side of his 

 forehead against the projecting rim of the eye-piece, and 

 looked towards the object with the right eye. The object 

 was hidden from the eye by the body of the microscope. The 

 body of the microscope was then raised by the coarse adjust- 

 ment until the object again just came into view, emerging 

 from behind the convex rim of the objective. This point of 

 adjustment was then marked (" scratch No. 2"). The operator 

 had thus four adjusted points : first, the tip of the nose ; 

 second, the side of the forehead ; third, the most convex part 

 of the rim of the objective; and fourth, the object. The 

 three first of these adjusted points were permanent, while the 



