BY C. A. SIEGFRIED, Surgeon U.S. Xavy. During t h e past few years Prof. Biitschli, of Heidelberg, has made many attempts, and now succeeds in producing under t h e microscope seemingly a m e b o i d movements. H e has communicated t o I'rof. Ray Lancaster, of England, a f u l l account of his methods by wliich lie attempts to imitate protoplasm. A medium sized match glass or flat dish m u s t be filled with a t h i n layer of common olive oil and be placed 011 a nnter b a t h or small cupboard a t a temperature of a b o u t LX" C'. T h e great point is to select t h e riglit moment a t wliich tlie oil attains t h e proper degree of tliickness a n d \ iscosity ; this moment citn, lio~vevcr,only be found by systematic trials. After three o r four days :I trial niay be made. Should tlie d r o p n o t Iiave become finely vesiculate aiid exhibit little o r no streaming, t h e heating process must be continued imd a trial made on the succeeding clay. If t h e oil becoriles too t h i c k it will form frothy drops: itrid i i i sucli citses a small quantity of ordinary olive oil must be mixed wit11 it. Tlie vcsicu1:tte drops i t r e tliiis 1)rcpared : I n L: small ag:bte mort a r a small quantity of dry carl~oiiateof 1)otitsll is ground to a fine powder. This is breatliocl 011 till the salt beeoincs slightly moist, a n d tlien :t d r o p of oil m u s t I)(; x d d e d ; tlic t w o coiistitucllts should be rnised until tlicy f o r m it tliickisli ptste. A few drops of tliis p s t i i , ahout the size of :t pin's 1ie:td or sni:tller, :tre placecl 011 ii c:o\.er glass, t h e CorIiers 01 wliicli itre su1)ported by 1)egs of soft 1):tr:tfKii. Tlien d r o p of water is placed on :i slide and t h e cov(:r glass is p u t oyer it i n such :t manner that t h e drops of p:Lste
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are immersed in the water, b u t are not much compressed. T h e preparation is then placed in a d a m p chamber, a n d remains there about twenty-four hours, when thc drops have a milk white a n d opaque appearance. T h e preparation is then well washed ont witk water, which is snpplied a t one edge by a capillary tube and d r a w n out by blotting paper a t another. If t h e drops hnve turned o u t well they will begin almost a t once, to move about rapidly and change their shape continuously. T h e water under t h e cover glass must now be displaced by glycerine diluted with a n equal bulk of water, when a vigorous streaming movement will be eshibited. T h e amceboid movements arc generally more distinct if the drops are somewhat compressed. If t h e drops do n o t stream they can be generally made to do so by slightly tapping t h e cover glass, by applying gentle pressure, or sometimes by breaking u p the drops. I t is especially interesting t o see how fast and beantifidly t h e drops creep to a n d fro in t h e water or half diluted glycerine, even when they are not compressed. Th(>streaming movement on t h e other hand is better seen if t h e drops arc somewhat coniprcssed ; this may be done by inserting under the cover glass a piece of broken cover glass of medium thickness, a n d t h e n removing tlie paraffin pegs. This strcnrning movemcnt is best demonstrated twenty-four hours after the addition of the glycerine, as the drops will t h e n be thoroughly cleared and transparent. T h e movement a n d streaming are much more marked and distinct if the drops are examined on a stage warmed t o 50” C. Prof. Biitschli advises repeated trials if the first experiments prove unsuccessful. Saponification, a n d vibratory movements inseparable from all inhabited spots, do n o t offer satisfactory solutions, a n d I take t h e liberty of asking t h e members of t h e Society for some little discussion regarding the probable causes concerned.
