134 TISSUES IN GENERAL. 



which contains the spokes or prickles connecting the elements. 

 Features similar to those of epithelia may also be exhibited by 

 some connective-tissue corpuscles, especially those of the medul- 

 lary tissue (osteoblasts) and the endothelium j the same are found 

 in the tissue of smooth muscle. I intend to demonstrate here- 

 after that the development of a unit of connective tissue is 

 invariably preceded by a stage which corresponds to the schema 

 of epithelial formation ; we are therefore not justified in making 

 an essential difference between the elements of connective tissue 

 and those of epithelium, exclusively based on differences in their 

 shape. 



Just as each independent protoplasmic lump, and within it 

 each vacuole, is bordered by a continuous layer of living matter, 

 so the body of a mammal, and in its interior every cavity, is 

 covered by a continuous layer of protoplasm. 



Based upon the facts hereinbefore described, we may obtain, 

 as I shall later show, a clear view of the development of the 

 tissues and of the inflammatory process. During inflammation, 

 especially that of certain tissues, conclusive proofs are furnished 

 that there is in the basis-substance a large amount of living 

 matter which is liable to become diseased. 



Is Blood a Tissue? As one of the consequences of the 

 modern views regarding individuals, it is held that blood, pus, 

 secretions, etc., are fluid tissues. I have demonstrated that every 

 animal tissue is a continuous mass of protoplasm, with zones of 

 different structure. An " intercellular substance" exists here as 

 little as u cells," in the modern sense, are present. We are 

 justified in speaking only of basis-substance. 



That single lumps, as migrating cells, discovered by Von 

 Recklinghausen, are, for a time, disconnected from other ele- 

 ments and execute locomotion of their own, does not alter the 

 general rule. Migrating corpuscles are not essential constituents 

 of a tissue. 



In the blood, isolated protoplasmic lumps, the red and colored 

 blood-corpuscles, float in a liquid plasma. Protoplasmic lumps 

 are likewise suspended in liquids such as pus, colostrum, bile, 

 sperm, etc. Such liquids we have no right to call tissues. 



The analogy between a living amoeba and the body of a 

 higher animal as to its living blood-corpuscles is apparent 

 enough. In the amoeba there arise transient vacuoles, in some 

 of which, as I have demonstrated before (see page 22), granules 



