128 



H. F. Formad, 



To be explicit, I must briefly narrate the minute structure 

 of connective tissue in general. 



The connective-tissue fibrils are in varying number united together 

 to form bundles (which I will, with Shakespeare, call the primary 

 bundles); these again occasionally unite to form larger bundles (well 

 designated as secondary bundles). The bundles arrange themselves 

 at different localities in various manner; in our specimens they de- 

 cussate at different angles and in all possible directions, leaving 

 between them small spaces which are dependent for their shape and 

 size upon the arrangement and the thickness of the bundles. These 

 spaces are essentially nothing else than serous cavities on a minute 

 scale. They communicate, however, with one another, and thus form 

 a system of channels continuous throughout the whole connective-tissue 

 system of the body. These channels are called lymph-spaces or juice- 

 channels. They contain normally a small amount of serum, and it is 

 also these spaces which harbour the enormous quantity of this fluid 

 when the tissue is the seat of oedema. Blood or air collects in these 

 spaces in certain pathological conditions, and we will also see that 

 inflammatory processes have here their main seat. 



There exists a special set of similar channels surrounding or 

 rather enveloping the blood-vessels, the so-called perivascular spaces, 

 the significance and purpose of which are the same as those of the 

 just- described interstitial lymph -spaces, with which they are also in 

 direct communication. These are very prominent in nervous tissues 

 and are best demonstrable in the brain, where the blood-vessels lie 

 nearly free in these spaces, giving a picture not unlike a piece of 

 wire inserted into a glass tube. In other localities these perivascular 

 spaces to not completely ensheathe the blood-vessels and are less 

 distinct, — in fact, are sometimes demonstrable only in some patho- 

 logical conditions. Under normal conditions both sets of channels 

 have the office or function of conducting serum from the blood-vessels 

 to the lymphatics, thus relieving excessive intravascular pressure. 

 They probably play, also, a very important rôle in the creation of 

 white blood -corpuscles from the endothelium desquamated from the 

 walls. Each of the connective-tissue bundles spoken of above is sur- 

 rounded by a distinct, not quite continuous, membrane composed of 



