TISSUES IN GENEEAL. 139 



" On the significance of these discoveries, and their bearing 

 upon the question of physiology and pathology, I can here say 

 but a few words. The more our knowledge of the minute 

 anatomy, or rather morphology, of the organism advances, the 

 more explicable becomes the functional activity of the various 

 parts and tissues. So long as the cell was looked upon as the 

 simplest form element of the body, we could not hope to go 

 beyond the cells, and their performances in health and disease. 

 Unfortunately, their investigation could not explain essential 

 vital phenomena, the real activity of living matter. To-day we 

 have it in our power to examine almost all tissues of the animal 

 body while they are alive, by preventing, in thin sections placed 

 under the microscope, evaporation or drying upon the one hand, 

 and by supplying, on the other, such artificial temperature and 

 other conditions as are necessary for the vital manifestation of 

 the particular tissue under investigation. And, enabled directly 

 to observe the phenomena which accompany movement of living 

 matter, its contraction, we may hope to attain clear conceptions 

 of the mysterious activity of muscles, of nerves, even of epithelia, 

 which form secretory organs. I may instance Heitzmann's dis- 

 covery of the manner in which primary muscle-bundles are 

 constituted, as showing how easy it is to understand the observed 

 phenomena of muscular contraction and innervation, if we have 

 correct information as to the morphological arrangement. With- 

 out going into the details, I may say that a primary bundle is made 

 up of rows of sarcous elements and muscle fluid, the former 

 united by threads of living matter, as mentioned before. Con- 

 traction of the whole muscle consists in this : that the sarcous 

 elements become larger, and the threads shorter. Kiihne has 

 shown that the motor nerve does not enter the muscle fiber, but 

 ends knob-like at its side, in about the middle 5 here the con- 

 traction commences, and proceeds toward each end. In fact, we 

 find everywhere that definite physiological functions depend 

 upon definite morphological arrangements, and we may well 

 make deductions from the latter as to the former. 



" Pathology will doubtless derive much advantage from the 

 bioplasson doctrine. We are enabled to observe quantitative 

 and qualitative changes of living matter in the smallest con- 

 stituents of the body. We know that the disposition of living 

 matter is different in different persons, and that, in the case of 

 increased supply of food, the reaction is different in strong and 

 healthy people on the one hand, and the sick and weak on the 



