OF THE GLOBULE OR CELL. 11 



a homogeneous mass (which is correctly speaking a globule) ; 

 this constitutes fissiparons propagation (one variety only of 

 which is the budding). The latter method is the most fre- 

 quent means of proliferation ; thus all globules resemble each 

 other, not only with respect to their mode of origin, but even 

 as to their primitive globular form. 



Function of the Globules. When once formed, globules 

 under the influence of certain excitants perform their func- 

 tions in different ways. One kind are simply endowed with 

 the property of changing their shape ; as, for instance, certain 

 globules of the skin of the batrachians, under the influence 

 only of light as an excitant, change from a spherical into a 

 stellate and even a fibrous form. 1 This change of form is what 

 was for a long time recognized under the name of contrac- 

 tion. So the blood globules, when exposed to oxygen, become 

 more flat than before, a phenomenon which can also be effected 

 by the presence of sodium chloride, and certain other neutral 

 salts ; and this would seem to prove that the change is due 

 to a chemical phenomenon. We could also cite as examples 

 of change of form or of contraction the movements of the 

 vibratile cilia, with which the free surface of certain of the epi- 

 thelial cells are provided, which movements certainly are con- 

 nected with cell life and in no wise dependent upon the 

 medium of the nervous system, since forty-eight hours after 

 death they can be made to reappear under the influence of 

 a dilute solution of potassa or soda. 



Finally, all that has been said of the cells under the head 

 of composition, tenacity of self-maintenance, the attraction 

 they exercise on certain chemical substances, their electro- 

 motor power, etc., constitute their life. Farther on these 

 elements of vitality will be considered separately for each 

 globule. It should, however, be here remarked that, wher- 

 ever in the organism vital manifestations are observed, these 

 are found localized in special cells ; for instance, certain cells 

 in the liver secrete bile, others sugar, or a glycogenic sub- 

 stance ; again sensibility is localized in the nerve cell, etc. 



cells cannot be formed spontaneously, it is not without interest, 

 nor, perhaps, without advantage, to find defenders for the ancient 

 theories and enemies to the new (cellular) doctrine. Science will 

 be thus placed in a position to furnish to the facts every support 

 which belongs to them, and the study of the tissues can but gain 

 thereby." 



1 These changes of form involve changes of color, even in 

 globules containing no pigment. 



