Dec, 1903.] Transmission of Acquired Characters. 27 



We may sum up these stimuli as nutritive, respiratory, mechani- 

 cal, thermic, perhaps electrical and finally, what some will have — 

 a stimulus due to irritability, a virtual vital force. Now one 

 school holds that there is no connection or direct communication 

 between germ cell and body cell,* while another says there is and 

 has shown that there is a possible means of communication by 

 certain protoplasmic bridges that are known to occur at least in 

 some cases. It is obvious what application this has to the sub- 

 ject in hand. The germ-cell in the multicellular forms, located 

 as it is deep in the tissues of the body and away from the sur- 

 roundings of the organism to which it belongs, may react in one 

 of two ways: it may react to simply the stimuli given by the cells 

 immediately surrounding it or to this p/us an effect induced by 

 something such as a nervous force, as was mentioned as a possi- 

 ble means of communication between more distant cells. The 

 existence of such a force is not countenanced b)^ modern biolo- 

 gists and it is useless to follow the theme longer. This leaves us 

 with but the hypothesis of Darwin which he termed that of Pan- 

 genesis. Darwin early saw the necessity of some such lij^pothe- 

 sis, if acquired characters are inherited, in accounting for a mean.^ 

 of communication between the body-cells and the germ-cells. In 

 place of a subtle force, Darwin postulated an actual material 

 transmission of a portion of the body-cell to the germ-cell. He 

 assumed protoplasm to be composed of pangens or corpuscles and 

 that these might pass from cell to cell carrying with them the 

 characters, hereditary and acquired, of the cell from which they 

 came. The pangens migrate from the body-cell to the germ-cell 

 and becoming resident there, are transmitted to the offspring, in 

 which they pass to the several parts of the body, thus reproduc- 

 ing the form of the parent. An acquired character could thus be 

 inherited. From other considerations Darwin was led to believe 

 strongly in the transmission of acquired characters and it is a 

 mark of farsightedness on his part when he saw the necessity of 

 some such hypothesis, and met it. It is well to note in passing 

 that the so-called Neo-Darwinians are more Darwinian than tlie 

 man himself, paradoxical as it may seem. Darwin believed, and 

 that strongly, in the transmission of the direct effects of environ- 

 ment and attempted to explain it, and it is only his followers 

 that have dropped it from the creed. 



So much, then, for the a priori condition of the subject. We 

 have seen that in unicellular forms, acquired characters are 

 inherited and that in so far, in nuilticellular forms, as we can 

 treat the germ-cell as a single cell, and apart from the somatic 



"The term "germ-ceU" is meant to desigate such cells as reproduce the parent form 

 —all other cells being "body cells." Obviously the argument which was originally 

 applied to sex-cells will apply to cases of vegetative reproduction equally well, as in cases 

 of budding, spores, polyembryony, etc. 



