168 



SCIENCE 



[N. S. Vol. XLVI. No. 1181 



likely due to new compounds. Often I have 

 seen considerable evidence pointing to the con- 

 clusion that in some cases the dyes fed are 

 converted into colorless compounds during the 

 process of digestion (a reduction phenome- 

 non), and these colorless compounds recon- 

 verted into colored substances after they arrive 

 at certain destinations or conditions. The 

 number of changes these " living laboratories " 

 can ring on the molecular structure of a given 

 dye must in some cases be very considerable. 

 Two or more dyes fed simultaneously some- 

 times produce results more or less independent 

 of each other. The spectacles are very bril- 

 liant. 



Using these methods I have been able to 

 demonstrate within the confines of a single cell 

 the existence of an unsuspected number of 

 kinds of " granules," manifestly playing dif- 

 ferent roles. After the differences among these 

 bodies have been shown in this way, it is some- 

 times possible to perceive corresponding morph- 

 ological differences ; but without the aid of the 

 color reactions the differences would never 

 have been suspected. 



The main thing to bear in mind is that on the 

 basis of our present more complete knowledge 

 of the chemical and physical properties of coal- 

 tar-derivatives these color reactions in living 

 nemas may be made the index of physiological 

 characters possessed by cells and their com- 

 ponents. In view of the great variety of the 

 known coal-tar derivatives, and the great va- 

 riety of physiological activities exemplified in 

 the free-living nemas, it seems to me a very 

 reasonable hope that researches directed along 

 this line will lead to important results, and 

 that the nemas may become classical objects in 

 cell and general physiology, as they have al- 

 ready become in sex physiology. 



A new and rather extensive nomenclature 

 will become necessary. It will be needful to 

 distinguish between the results of intra-vitam, 

 intra-mortem and post-mortem staining; for 

 these three terms represent as many different 

 phases in the chemical reactions that take 

 place during the course of the experiments. 

 As the cells lose vitality, new color reactions 

 occur, and the death of the cell is followed by 



further equally marked changes in the reac- 

 tions. 



The cell elements I have mentioned vary in 

 size, but most of them are exceedingly small, 

 many so small that they are on the limits of 

 visibility, using the very best instruments with 

 the greatest skill and under the most favorable 

 conditions. On the other hand, some of them 

 are large enough so that they can be examined 

 in considerable detail and their structures 

 made out. Among them are the bodies cur- 

 rently referred to under the name mitochon- 

 dria and other more or less synonymous words. 



As it will be some time before we can estab- 

 lish a rational nomenclature for these nu- 

 merous intracellular structures, it is desirable 

 meanwhile to adopt terms that will permit in- 

 telligent discussion of our discoveries as they 

 are made. While the principles underlying 

 such a nomenclature are easily defined, it is by 

 no means easy, in the present condition of 

 things, to suggest suitable short and expres- 

 sive roots to be used as a basis. There will be 

 less liability of confusion if the names first 

 employed relate to form, size and position 

 rather than to function. 



Investigations of this character are not un- 

 likely to stimulate further research in connec- 

 tion with aniline derivatives. Present efforts 

 are directed toward the discovery of dyes of 

 greater or less permanency. Permanency, 

 however, is of little moment in these investi- 

 gations; what is of moment is the chemical 

 composition and physical properties of the 

 dyes. 'No doubt dyes of a greater range of 

 composition can be produced if permanency be 

 disregarded. Furthermore, as already hinted, 

 colorless compounds may be used in intra- 

 vitam work if in the course of the metabolism 

 they are converted into colored compounds. 

 The results of recent studies of dies as chem- 

 ical indicators come into play, and give valu- 

 able evidence in determining acidity and alka- 

 linity. 



I am almost ready to express the opinion 

 that a small army of investigators should be 

 engaged on the problems opened up in this 

 way. The equipment needed by the investi- 

 gator is as follows: He must be a very good 



