Dkcejibek 27, 1895.] 



SCIENCE. 



895 



the optical appearances of protoplasm and also 

 in its peculiar movements simulate some of the 

 movements of living matter, while the same 

 physical explanation that applies to the move- 

 ments of the artificial froth will, it is claimed, 

 a,pply to the like movements in protoplasm. 



The evidence advanced by Prof Biitschli in 

 support of this foam theory may be convenient- 

 ly considered under the following four heads: 

 The structure of artificial foams; the observed 

 structure in many forms of living matter; the 

 movements of artificial foams; the movements 

 of protoplasm. 



His artificial foam is made by thoroughly 

 mixing in a mortar potassium carbonate with 

 olive oil that has been heated some time. A 

 drop of the oil lather so made is put on a glass 

 slip, covered with a glass cover and then soaked 

 in water; when cleared up with glycerine it is 

 ready to observe under the microscope. 



Such an artificial foam is seen under the 

 microscope to be made up of vesicles of oil 1-5 

 microns in diameter and vipwards. They are 

 full of water, alkali, soap and glycerine. The 

 whole mass of foam is fluid and flows under 

 pressure as oil does. Drops of this foam may 

 be kept for four to six weeks before the oil 

 vesicles burst. Some of the characters of 

 these foams most to be emphasized are: That 

 drops may enlarge or diminish by the osmotic 

 action of surrounding liquid; on the surface of 

 a drop, as well as in the interior on surfaces of 

 large intervesicular spaces, the minute vesicles or 

 alveoli are arranged in a layer of small cham- 

 bers quite regular in size, with their contiguous 

 faces at right angles to the free surface (this 

 is Biitschli 's ' alveolar border '); alveoli may be 

 arranged in radiating lines apparently by the 

 action of diifusion currents within the drops; 

 fibrous appearances may arise when currents 

 elongate the alvoli so as to extend lines of 

 them in one direction more than in others. 

 Other properties of these remarkable com- 

 pounds will be considered later in comparing 

 them with protoplasm. 



A considerable portion of the work is taken 

 up with a well-illustrated account of the struc- 

 tural appearances seen in the protoplasm of a 

 large number of different organisms. In both 

 living and in preserved protoplasm Prof. 



Biitschli demonstrates the almost universal oc 

 currence of a network appearance similar to 

 that caused by the oil vesicles in the artificial 

 foams. 



The methods employed consisted in : the use 

 of Zeiss apochromatic objectives 2 mm. Ap. 

 1.30 and 1.40 with eye pieces 12 and 18; an 

 iron-hisematoxylin stain made with ferrous ace- 

 tate and a,^ fo aqueous solution of hasmatoxylin; 

 an acid hsematoxylin made by adding acetic 

 acid to dilute Delafield's hsematoxylin; cutting 

 sections one micron thick and studying them, 

 often, in water instead of in balsam. 



Though no adequate idea of this net appear- 

 ance can be given without illustratious, a review 

 of the organisms in which the author has found 

 it may at least show the universal nature of its 

 occurrence. Among the Protozoa the group 

 Suctoria was examined in the representative 

 form Podophyra and a meshwork found in the 

 nucleus and in the body of the cell Avhile alive. 

 An alveolar layer was also seen. The group of 

 Ciliata show the network — living Vorticella, 

 Paramoecium, Stylonychia, and in the dead 

 stalks of Zoothamnium. In the Plagellata living 

 Chilomonas, in the Eadiolaria preserved Thalas- 

 sicolla, and in the Heliozoa living Actinosphseria 

 and Actinophrys sol all show the reticular appear- 

 ances. Amoebae, both living and prepared, show 

 the characteristic network appearances, while 

 amongst the marine Rhizopods with calcareous 

 shells, drops of viscid protoplasm crushed out 

 from living Miliolidfe show an alveolar border ; 

 in living Gromiathe transition from reticular to 

 apparently homogeneous protoplasm can be well 

 seen in the remarkable pseudopodia. 



Leaving the Protozoa, we note that in those 

 problematical forms the Myxomycetes, a retic- 

 ulum, as well as the important alveolar layer, 

 are seen in small masses of Aethalium septicum 

 fixed by a picrosulphuric-osmic mixture. Pre- 

 served Pelomyxa palustris also adds to the evi- 

 dence for the reticular appearances that may be 

 interpreted as foam structure. Among the 

 lower plants bacteria and some Cyanophycese 

 are claimed as presenting a nucleus-like portion 

 with an alveolar border surrounded, in some 

 cases, with protoplasm that presents the same 

 net appearance. 



Among the higher plants it is a noteworthy 



