732 SUMMARY OF CURRENT RESEARCHES RELATING TO 



small portion of an organ is taken from an animal that has been recently- 

 killed, with every precaution against Bacteria, and if this portion be placed 

 in a sterilized medium and treated in a digester, it can convert sugar into 

 acid and starch into glucose ; but the most careful investigation by the 

 Microscope and by cultivations cannot demonstrate the presence of microbes. 

 After some hours, the production of acid is arrested owing to that which 

 has been formed stopping the action of the protoplasm, but the formation 

 goes on again as soon as the acid is neutralized by a suitable quantity of 

 potash. The only difference between the action of the protoplasm and that 

 of microbes is one of quantity ; that being smaller in the former case. 



The author thinks that these experiments prove that the difference lies 

 in the reproductive power of the microbes ; he has nothing in common with 

 Liebig, for in his experiments the tissues do not decompose, but feed them- 

 selves and continue to live ; the only symjitom of decomposition is the 

 destruction of the nuclei. " A tissue removed from a healthy animal and 

 digested in a nutrient medium does not multiply, but it does live, and the 

 fermentation to which it gives rise is a proof of it." 



Embryo-chemical Investigations.* — Herr L. Liebermann has investi- 

 gated the chemical constitution of various portions of the eggs of fowls. 

 (1) The vitelline membrane was dexterously isolated, and purified, subjected 

 to various qualitative tests, and finally analysed. The average result of 

 analysis gave a composition unlike that of any known albuminoid, viz. 

 C 46-21, H 7-55, N 12-20, S 3-62, O 30-42, in percentages. (2) The 

 chalaza gave similar qualitative reactions, but the percentage composition 

 was different, e. g. C 48 • 26 or 47 • 94, H 9 • 81 or 8 • 07. (3) Tie membranes 

 penetrating the albumen also turned out to be different, e.g. C 50-95 and 

 H 7 ■ 24 per cent. The three substances are thus different from one another 

 and from albumen. They have had separate origins or have arisen from 

 albumen by different processes. 



Concentrated caustic potash not only swells the vitelline membrane, 

 but causes it to adhere to glass. Prof. Liebermann took advantage of this 

 to study the effects of reagents on the germinal disc. It was also tested 

 in situ. The detailed results are communicated. It consists principally of 

 albuminoid substances, but lecithin or something similar is also present. 

 The presence of sulphur (albumen) was also demonstrated in the germinal 

 spot, which became quite black after treatment with strong alkaline lead 

 solution. 



B. INVERTEBRATA. 



Otocysts as Organs of Locomotor Orientation.! — Prof. Y. Delage has 

 made a number of experiments with a view of determining the functions of 

 the otocysts of various Invertebrates. His results, put shortly, are to this 

 effect: the destruction of the otocysts produces a disorganization in the 

 power of locomotor orientation in animals subjected to it ; this result is due 

 to the abolition of the functions of the organ, and not to its excitation or 

 to the irritation of a nerve connected with it ; the almost total suppression 

 of visual and tactile sensations does not produce any effect of this kind ; 

 sicht and touch may, in a certain degree, take the place of the destroyed 

 otocysts, but in most cases the locomotor disorganization is only diminished 

 by the indications afforded by these two senses. The otocysts, in addition to 

 their auditory function, play the part of organs which regulate locomotion, 

 and they probably do this by provoking, in a reflex manner, the corrective 



* Math. u. Naturw. Ber. aus Ungarn, iv. (1886) pp. 66-77. 

 t Arch. Zool. Exper. et Gen., v. (1887) pp. 1-26. 



