M. RaspaiPs experirnents on the granules of Pollen. 101 



ration now pointed out, and the nature of my granules, I perform- 

 ed the following experiment. I placed on a very small drop 

 of water a grain of the pollen of mallbws. From the instant 

 of the explosion to the complete evaporation of the water, I 

 never lost sight of the insulated granules, during all the extra- 

 neous movements which separated them from the pollen. 



When they were applied against the surface of a plate of 

 glass I left them till next day without deranging the object 

 frame. Next day they had neither changed their form nor 

 their aspect, whereas after the evaporation of the water all ani- 

 malcules collapse, and become flat and crumpled in applying 

 themselves against the object-plate. My granules then resem- 

 bled exactly the resin deposited in mamillated masses, and upon 

 touching them with a microscopic point it made the same im- 

 pression upon them that it does upon plates of resin softened 

 by the mixture of a dissolving menstruum. 



I now poured upon my little flock a drop of alcohol, when 

 they were almostinstantly dissolved. But this menstruum makes 

 animalcules more easily seen, from rendering them opaque by 

 the coagulation of the albuminous juices with which they are 

 filled. 



The granules which Gleichen first considered as analogous 

 to spermatic animalcules, are therefore only little drops of re- 

 sin half dissolved, or of essential oil half concreted. 



In this experiment we must take into account all the de- 

 bris of glutinous or gummy tissues projected out of the pollen 

 with the granules, and which the use of alcohol renders more 

 perceptible by coagulating them. They then float in myriads, 

 and like black points. i 



It is on this account that these kinds of experiments ought 

 to be made by the person who desires to see them, for we 

 cannot expect to show them to another, for fear of the mis- 

 takes which could not fail to be committed in changing places. 



IV. Having found subsequently that those who are well ac- 

 quainted with the management of telescopes have very imper- 

 fect ideas both of the structure of the instrument, and of the 

 value of microscopical observations, I am compelled to enter 

 into farther details respecting the precautions which resear- 



