50 



THE AMERICAN MONTHLY 



[March, 



vation of some kind ; but probably the 

 faults are not of a kind that a student 

 or inexperienced microscopist would 

 be able to detect, or to point out with 

 any assurance. The writer of the ab- 

 stract quoted, need not grow despond- 

 ent because the fine figures in the 

 book are likely to be proven decep- 

 tions. The errors perpetuated in 

 books have greatly hindered the ad- 

 vance of knowledge and the discovery 

 of truth. Yet knowledge is advancing 

 in spite of them. 



Another course of reasoning, which 

 is exceedingly weak, has been sup- 

 posed to give support to the idea of 

 leticulated structure. It is said that 

 the movements of a homogeneous 

 jelly, such as protoplasm has been de- 

 scribed to be, would be impossible — 

 that some kind of reticulated structure 

 is necessary to enable us to explain 

 its power of movement. The absurd- 

 ity and weakness of this kind of argu- 

 ment are too apparent to deserve 

 further notice. At present it is merely 

 a question of fact whether there is 

 a reticulum or not. After its exist- 

 ence has been demonstrated it will be 

 time enough to theorize about how it 

 enables us to understand the phenom- 

 ena of life. 



The reticulum is supposed to ex- 

 plain the movement of living matter ; 

 movement is due to contractility, the 

 contractility resides in the nodes and 

 connecting threads of the net-work ; 

 the extension or contraction of the 

 net-work explains the movement of 

 the Amceba and the blood-cell. It is 

 an ingenious, mechanical explanation 

 of a mystery that has puzzled the sci- 

 entific world for ages. All the motions 

 of life are due to the contraction and 

 expansion of a reticulate structure, 

 which is common to all living things. 

 How easily all the observed facts are 

 explained ! What an admirable ma- 

 chine the Amoeba is! Perhaps some- 

 body will ask, by what means the reticu- 

 lum itstlf is enabled to extend and 

 contract. 1 am not aware that anyefifort 

 has yet been made to solve this prob- 

 lem. Enough, that the movements we 



see are explained upon mechanical 

 principles. Like the thousands of per- 

 sons who are satisfied to understand 

 mesmerism as animal magnetism, and 

 strange phenomena as due to elec- 

 tricity in the air, these gentlemen 

 present, in the name of science, an 

 explanation that does not explain. 



The sources of error in microscop- 

 ical observation are: i. Improper 

 illumination. 2. Imperfect correction 

 of the objectives. 3. Incorrect focus- 

 sing. The first source of error does 

 not concern us in the case under con- 

 sideration, for no special niceties of 

 illumination are required. The sec- 

 ond is of more consequence ; but, in 

 order to eliminate it from my own ob- 

 servations, I have used objectives 

 which were either adjusted by the 

 makers and set in fixed mountings, so 

 that their corrections could not be 

 changed, or else I have adjusted the 

 lenses myself by the use of suitable 

 objects, so that their correction was 

 as perfect as possible. Finally, errors 

 of focussing alone remain as the only 

 ones which cannot be absolutely elimi- 

 nated. Yet these, in the special ob- 

 jects of study, the Amceba and the 

 blood-cells, are of no consequence 

 whatever; for no experienced observer 

 can be in doubt as to the exact focus 

 for a white blood-corpuscle. 



A few words now about the appear- 

 ance of blood-corpuscles when highly 

 magnified. The red corpuscles, when 

 examined in the serum, are double 

 concave disks. When lying flat, in the 

 focus of a good objective, they appear 

 to be quite homogeneous in structure ; 

 the central portion of the disk, owing 

 to the concave shape, appearing 

 slightly darker than the rest. I am 

 not aware that it is claimed that a re- 

 ticulum can be seen in the red corpus- 

 cles under such circumstances. To 

 demonstrate the net-work it is neces- 

 sary to use some reagent, and a satur- 

 ated solution of potassic bichromate, 

 diluted with about an equal volume of 

 water, is recommended for the pur- 

 pose. The addition of such a solution 

 to fresh blood i)roduces a great change 



