CKNTIJES OF NUTRITION. 391 



Tliorc is one form in which nutritive centres are arranged, 

 both in healthy and morbid parts, wliich is frequently alluded 

 to in the following chapters, and which may be named a 

 germinal membrane* In a germinal membrane, the nutritive 

 or germinal centres are arranged at equal or variable distances, 

 and in certain directions, in Uw. substance of a fine trans- 

 parent membrane. A germinal membrane is occasionally 

 found to break up into portions of equal size, each of which 

 contains one of the germinal centres. From this it is per- 

 ceived that a germinal membrane consists of cells, with their 

 cavities flattened, so that their walls form the membrane by 

 cohering at their edges, and their nuclei remain in its sub- 

 stance as the germinal centres. 



Germinal membranes are only met with on the free 



centre, and more especially of the appearance of new centres within tlie ori- 

 ginal sphere, we are indebted to the researches of Dr. ilartin liany. "NMiat- 

 ever may l)e saiil in oppjsition to Dr, Barry's views regarding the functions of 

 the blood -globides, and the structure of muscular fibre, he is yet entitled, 

 above all physiologists of the present day, to the merit of having kept steadily 

 before liini in his researches the principle of the central origin of all organic 

 fonn. 



* The membranous tubes of glands on which the epithelium is situated 

 were described by Henle, Miiller's Arddv, 1839. ^Mr. Bowman {Phil. Trans. 

 1842) " On the Structure and Use of the Malpighian Bodies of the Kidney," etc., 

 has applied to the membrane of these tubes the verj- appropriate name of 

 Ba.sement Membrane. This membrane I consider to be a primary or germinal 

 membrane. The term, basement menibrane, is good as invoh-ing no 

 hypothesis ; it is therefore a most approijriate descriptive term. I have always 

 considered the basement membrane, or elementary membrane of glands, as a 

 form of the primary cells of glands, and the source of the secondary or 

 secreting cells, anil have therefore been in the habit of naming it primapi*, or 

 germinal membrane. Sir. Btiwnian considers it to be simple, or homogeneous. 

 This is true as far as it contains no bloodvessels, and as regards its external 

 or attached layer ; but as in its original condition it consists of cells, and when 

 perfect contains nuclei at equal or variable distances, I do not consider it as 

 simply molecular. These nuclei, or germinal spots, may Ix- certain of the 

 epiUulial cells, which become mother-cells, bttween the two layers of the 

 membrane ; or cells belonging to the order of tlie nuclear fibres of Valentin 

 and Henle. 



