1891.] On the Structure of Amoeboid Protoplasm, Sfc. 193 



periods of time, necessitating the maintenance of a nearly equable 

 temperature, and the remaining at rest for many hours, before the 

 top part of the mass becomes sensibly free from suspended portions 

 of the heavier alloy, and the bottom part from similar portions of 

 lighter alloy. The analytical numbers obtained on examining different 

 layers of the compound ingots prepared in the experiments described 

 in the earlier parts of these researches long ago convinced us of this ; 

 but, in addition, an actual visible presence of suspended particles of 

 one alloy in the midst of another, even after 8 hours tranquil fusion, 

 may be often observed in the case of silver-lead-zinc and silver-bismuth 

 alloys \\here the proportions of metals used are such as to form 

 mixtures containing considerable amounts of Ag 4 Zn 5 : by the aid of 

 a lens, or even with the naked eye, red particles disseminated through 

 a much lighter coloured matrix can often be distinguished on 

 examining the central portions of an ingot that has been filed smooth 

 and bright, and then kept for awhile so as to allow the red tinge to 

 develop. 



" On the Structure of Amoeboid Protoplasm, with a Com- 

 parison between the Nature of the Contractile Process in 

 Amoeboid Cells and in Muscular Tissue, and a Suggestion 

 regarding the Mechanism of Ciliary Action." By E. A. 

 SCHAFER, F.R.S. Received January 26, 1891. 



It has been shown by the researches of numerous histologists, of 

 rhom Heitzmann and Frommann, and, in this country, Klein, must be 

 skoned the pioneers, that the protoplasm of many cells exhibits the 

 ippearance of a network containing an apparently homogeneous 

 iterial in its meshes. The network is known as the reticulum or 

 Bioplasm, the clear material in its meshes as enchylema (Carnoy) 

 jr hyaloplasm. In many cells it is not difficult to observe this 

 structure even without the addition of reagents, but in amoeboid cells 

 ich as the white blood corpuscle and the amoeba it is less obvious, 

 id its presence has not been generally conceded. Recently, 

 afessor Strieker* has published a photograph of an amoeboid white 

 lood corpuscle, taken instantaneously by aid of the electric light, 

 rhich shows the reticular appearance in quite an unmistakable 

 iner; it must be granted, therefore, that the amoeboid white, 

 lood corpuscle also has this structure. 



Previously to the appearance of Professor Strieker's photograph, I 

 id myself for some time been engaged in investigating the structure 

 amoeboid cells with the aid of photography. Being unprovided 



* ' Wiener Medic. Jahrb.,' 1890. 



