SPONTANEOUS GENERATION. 15 



very tips. When, therefore, any living thing is seized upon, it is 

 at once enveloped in a glairy mass (a), which is formed by the 

 pseudopodia fusing their sides together ; and in this temporary 

 stomach the nourishment is extracted from the victim, and car- 

 ried in the circulation to the main part of the body. 



I think this will suffice to show you what is the extent of the 

 duties which these simple creatures perform. It is true that 

 their functions are not very complicated, but yet they are far 

 more so than any one, knowing their simplicity, would suspect 

 them to be capable of. 



Were you to imagine these chemical elements, Carbon, Hy- 

 drogen, Oxygen, and Nitrogen, (C H O N,) to be united in the 

 most simple manner, in order to form some animate creature, 

 you could hardly produce a more lowly organized being than 

 these self-same Amcebas which I have illustrated here. They 

 are, in truth, among the lowest of all animals known. 



While we are engaged upon this part of our subject, it would 

 seem to be most fitting to introduce here a description of some 

 experiments which were made to ascertain under what condi- 

 tions these rudimentary forms of life may originate. I will refer 

 to only one set of experiments, because they seem to be, by far, 

 the most satisfactory of any that have been made. 



In July, 1862, Professor Jeffries Wyman, of Harvard Univer- 

 sity, Cambridge, Mass., published, in the " American Journal of 

 Science," a paper whose title runs thus, 



" Experiments on the formation of Infusoria in boiled solutions 

 of organic matter, enclosed in hermetically sealed vessels, and 

 supplied with pure air." 



I propose now to make some extracts from that paper, and 

 illustrate what is therein stated by these diagrams. After some 

 preliminary remarks, Professor Wyman proceeds thus : 



" In order that the reader may understand what precautions 

 were taken, we shall first describe the manner in which the ex- 

 periments were performed." 



" (1.) In some instances (as in Expts. i. to v., vii. to xi., xiii. 

 to xv., xxix. and xxx. inclusive) they were prepared as in fig. A. 



