134 



SCIENCE. 



[N. S. Vol. V. No. 108. 



the nuclei of the sole are nuclei of the sai'- 

 coplasma. The axis cylinder of the motor 

 nerve ends in an end-brush in the sar- 

 coplasma. The neurilemma becomes con- 

 tinuous with the sarcoplasma. 



B. Heart muscle (cat and dog). Axis 

 cj'linders of sympathetic ganglion cells ter- 

 minate on the heart muscle cells either as 

 very simple endings, namely, one or two 

 very fine end-branches which terminate in 

 small granules or bulbs, or in somewhat 

 more complicated end-organs composed of 

 several small twigs, these usually ending 

 also in the bulbous enlargement. 



C. Involuntary muscle (cat, rabbit and 

 tortoise). The ending here is very simple. 

 The terminal branches of the axis cylinders 

 course along between the involuntary muscle 

 cells, giving off in their course very fine 

 side branches which end on the cells often 

 near the nucleus. 



The functional develoimient of the cerebral cortex 

 in different groups of animals. W. Mills. 

 The dog, cat, rabbit, guinea pig, rat and 

 mouse were studied. Only those animals 

 were used whose exact age was known, and 

 ether was the ansesthetic invariably em- 

 ployed. The research was carried on in 

 connection with investigations on the psy- 

 chic development of the same animals. The 

 following are among the most important 

 conclusions drawn : 



In the dog, cat, rabbit (and, in so far as 

 the author's experiments go, in the rat and 

 mouse) neither the brain cortex nor the un- 

 derlying white matter is excitable by elec- 

 trical stimulation at birth or for some days 

 afterwards. The cortex is usually not ex- 

 citable till about the period when the eyes 

 open, though there are exceptions to this 

 rule, most frequently in the author's ex- 

 perience in the cat, in favor of an earlier 

 date. The white matter of the brain just 

 beneath the cortex is generally excitable 

 either at an earlier date than the cortex or 



with a weaker stimulus. The reaction for 

 the limb movements is obtainable invari- 

 ably somewhat earlier in the dog and the 

 cat, and generally so in the rabbit, than 

 those for the neck, face, etc. Localization 

 for the cortex, and still more for the white 

 matter, is at first ill defined, but gradu- 

 ally, though rapidly, becomes more definite. 

 In the cavy (guinea pig) the cortex and the 

 white matter beneath are electrically ex- 

 citable either at birth or a few hours after- 

 wards, and perfection of reaction and locali- 

 zation is reached in a few days. Before 

 the brain cortex responds to electrical ex- 

 citation, ablation of the motor area (cen- 

 ters) leads to no appreciable interference 

 with movements. The younger the animal 

 the stronger the current required to pro- 

 duce reaction up to the time that localiza^ 

 tion is well established, i. e., the weakness 

 of the current required to cause a move- 

 ment is an indication of the degree of de- 

 velopment of the center in question. Dif- 

 ferences for breeds and individuals exist 

 and constitute to some extent exceptions to 

 the above general statements. 



In the above, ' cortex ' refers to the gray 

 matter in or near the motor area, and ' white 

 matter ' to the brain substance immediately 

 beneath . 



The restoration of coordinate power after nerve 

 crossing. E. H. Cunningham. 

 Eead by title. 



The proteolytic action of papain. E.. H. Chit- 

 tenden. 



The exact relationship of the vegetable 

 proteolytic enzymes to the corresponding 

 enzymes of animal origin has never been 

 quite clear. The conditions governing the 

 action of both papain and bromelin indicate 

 a closer relationship to trypsin than to pep- 

 sin. The products found, however, appear 

 to differ somewhat both chemically and 

 phj^siologically from the corresponding 

 products formed by animal enzymes. Brom- 



