342 MOHL'S PROOF THAT [BOOK n. 



M. Schultz's theory of the latex appear erroneous. "By 

 placing a small quantity of latex between two slips of glass, 

 and sliding these over one another, it may easily be seen that 

 the globules are composed of a softish, very viscid matter, that 

 pressure unites them, and that there is no trace of an enve- 

 loping membrane ; they may be collected and drawn out in a 

 stringy mass, beneath the microscope, with the point of a fine 

 needle. When a thin layer of latex is dried on glass, the 

 liquid in which the globules float is changed into a trans- 

 parent crust, which may be dissolved in water so as to 

 re-establish the original condition of the sap. This dried 

 serum forms a brittle mass, which, like a thin layer of gum, 

 breaks with sharp angles, while the globules retain their 

 original form and condition. When 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 illusion." Thus it is " seen that the globules are des- 

 titute of any trace of organisation, and can no more be com- 

 pared with blood-corpuscles than can any other drops of resin, 

 oil, &c., met with in vegetable fluids. The caoutchouc of the 

 latex cannot 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. 



The mutual attraction and repulsion of the globules and 

 the walls of the vessels, the autosyncrasy and autodiacrasy of 

 M. Schultz, Professor Mohl sets down as pure creations of 

 fancy. He says that they are nothing more than ordinary mole- 

 cular motion, and take place equally in fresh latex and that 

 which has been diluted with water or dried and re-dissolved. 

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

 M. Schultz, independent of external influences; Professor 

 Mohl states that the latex in its natural condition is in a 

 state of absolute repose. By bringing portions of uninjured 

 plants of Chelidonium beneath the microscope, he found that 



