230 NOTES AND MEMORANDA. 



papers in various languages or with varying contents would 

 look alike at the distance of a third of a mile. 



3. General Conclusions to he deduced from the above Facts. 



When we com^ to the application of these principles to the 

 study of living matter, we are immediately led to feel how 

 very little we know respecting some of the most important 

 questions that could occupy our attention — questions which 

 certainly never presented themselves to me, until I looked 

 upon them from this point of view, and which perhaps have 

 not occurred to any one before. As illustrations of the sub- 

 ject now under consideration I do not think 1 can select better 

 than the facts bearing on the size and character of minute 

 germs, and on Darwin's theory of ultimate organized 

 gemmules, as described in Part ii, chapter xxvii, of his work 

 on the variation of animals and plants under domestication. 

 So far as I have been able to learn, he has nowhere given 

 any opinion as to the probable size of such gemmules, nor 

 discussed the probability of some of his speculations when 

 examined from a numerical point of view, and in connection 

 with the probable size of the ultimate molecules of organized 

 matter. I therefore propose to do so ; since, though not 

 actually a microscopical question, it is most intimately con- 

 nected with our studies, and as microscopists I think we 

 have a good claim to investigate objects that are just beyond 

 our magnifying powers. 



For the sake of simplicity I will take into consideration 

 only the albuminous constituents of animals, using the term 

 albumen in a sort of generic sense, to include many com- 

 pounds, which differ in many particulars, and yet have many 

 in common. With slight modifications the same principles 

 would apply in the case of other substances. Whatever be 

 the special variety of this constituent, it is so associated 

 with water in living tissues that in most, if not in all, cases 

 they would cease to live if thoroughly dried. This is 

 exemplified by the case of hair and horn, which must con- 

 tain much water at the growing end, but are dead where 

 hard and dry. In living tissues much of the water is no 

 doubt present simply as a liquid mechanically mixed with 

 the living particles, but it appears to me that we ought to 

 look upon some portion as being in a state of molecular 

 combination. So little attention has been directed to this 

 kind of weak ajffinity, that its very existence is almost or 

 quite ignored in many large and important chemical works, 

 and yet probably many of the phenomena of life are mani- 



