880 OF GENERATION GENERAL CHARACTER OF THE FUNCTION 



mated, exhibit evidences of life. The fluid such, for instance, as an in- 

 fusion of turnip, carrot, meat, cheese becomes cloudy, from the formation 

 or separation of au infinite number of minute molecules, almost unresolv- 

 able by the highest microscopic powers. Soon Bacteria, or small rod-shaped 

 bodies appear, which exhibit movements of a slow oscillating character, 

 then more swiftly moving monads and vibrios, and, finally, infusoria of va- 

 rious forms and more complex structure. Two views have been advanced 

 to explain the development of these lowly organized beings. On the one 

 hand, the panspermists maintain that the air is crowded with spores so small 

 as to be imperceptible to the highest microscopic powers, and which, falling 

 on suitable soil, as into moist solutions of organic substances, immediately 

 begin to increase and multiply; and they point to the fact that the purer the 

 air, whether it be that obtained on high mountain-tops, or which has been 

 filtered through cotton-wool, or has been made to pass through red-hot tubes, 

 the less likely is the solution, if protected by closing the mouth of the ves- 

 sel in which it is contained, to become the seat and focus of life. On the 

 other hand, the heterogenists contend that, as on the Darwinian theory 

 pushed to its furthest limit, the whole animal and vegetable kingdoms may 

 be derived from some simple form, which must have originated from the action 

 of light and heat, or of heat alone, on the inorganic materials of which the 

 earth is composed, it is not unlikely that the same process is constantly being 

 repeated when the appropriate conditions are present ; and they point as 

 additional arguments in favor of their view, to the circumstances that, what- 

 ever may be the care taken in filtering the air admitted to organic infusion, 

 and even when a boiling temperature has been maintained for several min- 

 utes with hermetic closure of the vessel during the process of ebullition, it 

 is, in many cases, impossible to prevent the development of bacteria, though 

 the absence or great diminution of air or rather of oxygen thus occasioned 

 prevents them forming in any considerable numbers. They refer also to the 

 extraordinary numbers in which the bacteria appear numbers which they 

 believe to be incompatible with their production from the spores supposed 

 by the panspermists to be floating in the air; and, lastly, they refer to vari- 

 ous experiments which seem to show that the lowest forms of life may be 

 germinated in solutions, consisting exclusively of inorganic compounds. 

 When it is considered how difficult it is to preserve the air admitted to the 

 solution used in these experiments in a perfect state of purity, and our 

 ignorance of the amount of heat which the spores of the lower organisms 

 can bear exposure to without destruction, it would seem at present that it is 

 safest to hold the doctrine of panspermism, though it must be admitted to 

 present several points of considerable difficulty. 1 



728. Among Plants, and the lower tribes of Animals, a multiplication of 

 independent beings takes place without any sexual process whatever, by a 

 process of gemmation or "budding" from the parent stock ; these "buds," 

 at first entirely nourished by it, gradually become less and less dependent 

 upon it, and at last detach themselves and maintain a separate existence. 

 Now this process may be regarded as essentially the same with that of the 

 multiplication of cells by subdivision, which is one of the most ordinary 

 operations of growth and development ; and it is peculiar in nothing else 

 than this, that the newly formed structure, instead of remaining as a con- 

 stituent and dependent part of the parental fabric, is capable of living 

 independently of it, and of thus existing as a distinct individual wheu 







1 Tho student will find a very full discussion, with an historical resume of this sub- 

 ject, in Dr. Bastian's Beginnings of Life, 1872; Bunion Sanderson, Nature, vol. viii, 

 p. 478; Heuzingii, Samuelson.'Putzeys, and Gscheidlen, in Pfliiger's Archiv for 1873 

 and 1874. 



