56- THE SCIENCE OF LIFE. 



the two liquids have for each other and for the mem- 

 brane separating them. 



Crystallizable bodies, as salt, niter, etc., when in solu- 

 tion, and substances allied to them, as hydrochloric acid, 

 and alcohol, pass readily through membrane ; but bodies 

 which do not crystallize, but assume the gelatinous form, 

 as gum, starch, albumen, hydrate of alumina, etc., pass 

 through, if at all, with great slowness. Such bodies are 

 called colloid, or glue-like. Osmose occurs through all 

 jelly-like bodies, as bioplasm, as well as through fully 

 formed membrane, and in this manner various liquids 

 are absorbed or imbibed by the tissues. 



5. Molecular coalescence is a term applied to the modi- 

 fication of ordinary forms of inorganic particles which 

 occurs when they combine in the presence of organic 

 matter. Thus it has been found that the crystallization 

 of certain salts of lime, as the carbonate, when occurring 

 in a solution of some organic colloid, as gum-arabic, al- 

 bumen of eggs, blood-serum, and gelatine, is so modified 

 by such a solution as to resemble many of the calcareous 

 deposits found in nature. 



The bottom of the middle and northern parts of the 

 Atlantic Ocean is found by the deep-sea dredge, even 

 at the depth of nearly three miles, to be covered with a 

 sort of slimy ooze, which Prof. Huxley formerly deemed 

 to be of animal nature, and termed Bathybius. More 

 recent investigations have led him to change this opin- 

 ion. It is regarded as a gelatinous inorganic secretion, 

 or a product of Diatoms, a family of minute Algae. In 

 this slime great numbers of globular, shell-like micro- 

 scopic masses are found, similar to those in the chalk 



