442 Prof. H. Mohl on the Latex and its Movements. 



retain their original form and condition. Wlien this dried mass 

 is exposed to the air for about twenty-four hours, particularly if 

 placed in the sun, the elastic substance of which the globules are 

 composed contracts in the cavities of the serum, presenting the 

 appearance of vesicular membranes containing nuclei ; but the 

 solution of the serum in water clearly proves this to be an illu- 

 sion. 



From the above, it evidently results that caoutchouc is neither 

 contained in the serum nor does it inclose the globules when 

 dried, since the serum dissolves easily in water and dries into a 

 brittle crust, which cannot be a membrane of caoutchouc, as M. 

 Schultz called it. From the physical structure of the globules, it 

 is hardly to be doubted that they contain caoutchouc, though pro- 

 bably it is often combined with other substances. When a layer 

 of dried latex is macerated in alcohol the globules are not dis- 

 solved, but when the dried serum is redissolved in water it con- 

 tains numerous little brownish flocks (coagulated albumen ?) . 

 When dried latex is macerated in sether, the dried serum is found 

 to contain, not globules, but open cavities filled with air ; no trace 

 of viscous matter remaining, but the crust of serum very brittle. 



iEther only determines a coagulation of the latex, inasmuch as 

 it liquefies the globules, and at its evaporation leaves them in the 

 form of a membrane. Alcohol acts differently ; it mixes with the 

 latex and separates white membranes from it. By means of the 

 microscope, these membranes are seen to be formed out of a sub- 

 stance separated from the serum, having a granular appearance, 

 lax cohesion, and absolutely devoid of viscosity ; they inclose a 

 number of unaltered globules. Prof. Mohl suggests that this 

 substance may be albumen. 



From the foregoing it will be seen that the globules are desti- 

 tute of any trace of organization, and can no more be compared 

 with blood-corpuscles than can any other drops of resin, oil, &c. 

 met with in vegetable fluids. The caoutchouc of the latex can- 

 not be compared with the fibrine of the blood, since it is not met 

 with, as that is, in solution in the serum, and does not transform 

 this latter into a plasma ; it is met with, on the contrary, in a 

 complete state of development under the form of globules. 



2. Movement of the Latex. 



The mutual attraction and repulsion of the globules and the 

 walls of the vessels, the autosyncrasie and autodiacrasie of M. 

 Schultz, our author sets down as pure creations of fancy. He 

 says that it is nothing more than ordinary molecular motion, and 

 takes place equally in fresh latex and that which has been di- 

 luted with water or dried and redissolved. 



The movement in the form of a current is, according to M. 



