36 THE ARRANGEMENT OF THE 



diately by coalescence of the flat layer. Obviously, the bursting 

 must be due to a sudden and intense contraction of the reticulum 

 close behind, and as the foreign particles are often driven out 

 with a certain force, like a shot, we may conclude that, together 

 with the foreign body, also a certain amount of liquid has escaped 

 from the interior. A momentary reestablishment of comparative 

 rest in the contracted portion would seem to be required for the 

 coalescence of the separated portions of the outer flat layer. A 

 part of the reticulum itself may penetrate the investing layer, or 

 a single granule with adhering filament. The result will be a 

 small protrusion, or a single granule attached to the outer surface 

 by a slender pedicle. 



Analysis of Vacuoles. A vacuole is a lake in the middle of the 

 protoplasmic body, inclosed by a continuous layer of living matter. 

 Without such an investing wall the lake could not be formed. 

 The vacuole may increase in size, either by stretching of the 

 encircling layer, or by confluence with a neighboring vacuole, if 

 the wall between the two should break. The vacuole may sud- 

 denly appear, and also suddenly disappear. Granules of living 

 matter are sometimes floating in the lake ; sometimes offshoots 

 of a granule reach the inner surface of the wall of the vacuole, 

 and the reticular structure is immediately reestablished. Vacu- 

 oles may be formed, and may disappear suddenly, in ways and 

 for reasons which we do not understand as yet. Formerly, the 

 vacuoles were thought to be stomachs of the protoplasm, an 

 assumption for which we have no ground whatever. Embryo- 

 logical research, on the contrary, proves that vacuoles are ele- 

 mentary vascular organs, containing plasma; as E. Klein first 

 demonstrated, the heart and the blood-vessels are originally 

 nothing else but vacuoles. 



Comparison of Amoeba and Man. The analysis of a single 

 protoplasmic lump is of the greatest importance, inasmuch as 

 such a lump is the simplest animal organism, on the plan of 

 which are built up all, even the most complicated organisms. 

 It will be demonstrated farther on that the human body is con- 

 structed on the plan of an amoeba, and the comparison will be 

 carried out in all details. Man is a complex amoeba with per- 

 manent protrusions, the extremities, with a wonderfully compli- 

 cated division of labor of the groups of the living matter. Man, 

 in totOj is an individual, as is the amoeba, and in both, isolated 

 lumps of living matter float about in the one case in vacuoles, 

 in the other in the blood and lymph vessels. 



