XIV, 4. Andrews: Preservation of protoplasmic spinnings. 447 



As to the usefulness of this light-filter, I may State that in mi- 

 croscopic work I nse it exclusively, much preferring it to daylight. 



In order to get the füll benefit of this light , the objective 

 should iirst be focused on the tissne of the object ; the ocnlar should 

 then be removed and the condenser raised or lowered until the 

 raeshes of the mantle of the light are distinctly reflected by the 

 condenser into the objective. The light is then as strong as it can 

 be made. If a Zeiss apochroinat 2 mm, 1'40 aperture be used, 

 only a few meshes can be seen, but they must be perfect and not 

 distorted in any way. 



After it has once been properly gaged no further adjnstment 

 of the condenser is necessary, as the light cannot then be improved. 



The sliding racket used on the Welsbach light is a great 

 convenience, as with this, the light may be kept always burning or 

 glowing, and by simply pulling the chain it may be brought into 

 füll glare without the necessity of lighting each time. 



California Academy of Sciences, San Francisco, California. 

 January 22, 1898. 



[Eingegangen am 28. Februar 1898.] 



On a method found useful in preservation 

 of protoplasmic spinnings. 



By 

 Gr. F. Andrews, 



Baltimore, U. S. A. 



While carrying on at the Marine Biological Laboratorv, Woods 

 Holl. Mass., in 1893, certain observations on protoplasmic spinning 

 in Echinodern embryos, * I made a series of tentative experiments 



x ) Described by me in recent issues of the Journal of Morphology, 

 under the titles of „Some spinning activitics of protoplasm in starfish and 

 Echinus eggs" and „The living substance: as such and as organism' - 

 (vol. XII, no. 2; and vol. XII, Supplement). 



