September i6, 1892.] 



SCIENCE. 



161 



were not wisely chosen, the facts in the case not being before me, 

 I am free to confess that I have grave doubts whether they were 

 even as well adapted to the purpose as the ordinary dry plates. 

 In any case, the best work on the corona has yet to be done, with 

 plates prepared for that special purpose, and with apparatus spe- 

 cially arranged. Several efforts have been made in this direction 

 abroad, not with entire satisfaction it is true, but they indicate a 

 recognition of progress in photographic work, and a laudable dis- 

 position to apply the latest knowledge to special requirements. I 

 am not aware that any photographic experiments are now under 

 way in anticiiiation of improved methods to be applied to the so- 

 lar eclipse next year. If not, we have no reason for expecting 

 any better photogi'aphs of the corona than those of Professor Hol- 

 den, which are doubtless as good as can be made without special 

 plates. Let me add as a purely gratuitous opinion, founded, how- 

 ever, upon long consideration of the subject, that I am convinced 

 of the practicability of photographing the corona without waiting 

 for an eclipse. To do this, however, would require no small 

 amount of preliminary work, for which a well-equipped laboratory 

 is necessary. 



Not wishing to extend this communication to undue length, I 

 confine my remarks to these few eminently practical subjects for 

 laboratory research, only adding that there are many others which 

 deserve investigation, such as photographic standards of light and 

 color, methods of recording daily solar activity, the comparison of 

 the chemical and visual effect of light of various colors, — a very im- 

 portant subject in stellar photography, — atmospheric absorption, 

 the application of photography to meteorology, the formation of 

 clouds, lightning, and a host of other subjects which will suggest 

 themselves. 



The point I wish specially to make is that a photographic re- 

 search laboratory would be of the greatest value as an aid to re- 

 search in many branches of physical investigation. It has been 

 my privilege to visit the laboratories of Dr. Eder in Vienna and 

 Dr. Vogel in Berlin, both of which have contributed so much to 

 a practical and scientifio knowledge of photographic methods; 

 but above either of these, for purely scientific research, I should 

 say the private laboratory of Mr. Schumann, in Leipzig, although 

 much more restricted in scope, approaches nearer to my ideal of 

 what we most need in this country. 



I trust that these few words will receive such favorable conf id- 

 eration and support from the scientific men of the country — espe- 

 cially from those who have experienced the shortcomings of pho- 

 tography in recording the results of their work — as they may 

 seem to deserve, and that a laboratory such as I have indicated 

 may soon be established either in connection with one of our large 

 universities or by private endowment. 



The Woodmont, Washington, D. C, Sept. 9. 



THE RETICULATED PROTOPLASM OF PELOMYXA. 



BT DR. ALFRED C. STOKES. 



Within recent years the structure of protoplasm has been much 

 studied by microscopists, and the several theories enunciated have 

 attracted considerable attention and been the subject of considera- 

 ble discussion. The entire subject is a fascinating one, but 

 among all the doctrines put forth by various observers, either as 

 the result of personal investigations with modern high-power ob- 

 jectives, or as a result of a working of the ' ' scientific imagina- 

 tion," none has received more attention of a certain kind, and 

 none is more pleasing, than Dr. Carl Heitzmann's theory of the 

 reticulation of the protoplasm. Yet simple and beautiful as his 

 doctrine is, it has been ridiculed and summarily dismissed by those 

 that have failed to obtain results similar to his. 



Dr. Heitzmann claims that all animal protoplasm is at all times 

 a net-work of delicate threads, in v/hich is the life of the object, 

 the meshes thus formed containing the liquid or semi-liquid and 

 other non-living constituent parts of the protoplasm. His book 

 on the " Microscopical Morphology of the Animal Body in Health 

 and Disease " is somewhat surprising, since he sees all tissues as 

 formed of reticulated protoplasm, an appearance that he seems 

 to have no difficulty in demonstrating, but which the majority of 



microscopists and histologists claim to be unable to see, and which 

 they say is therefore non-existent. The subject merits further 

 attention. Judging from a limited experience, but from an ex- 

 perience gained through an eye to a certain extent trained in 

 microscopical examination with high powers, I am willing to con- 

 fess that the Heitzmann doctrine of the structure of protoplasm is 

 more than satisfying; if it should be proved to be illusory or the 

 result of the action of reagents, I should be disposed to abandon 

 it with regret. 



In 1873, Dr. Heitzmann, before the Vienna Academy, demon- 

 strated the reticular structure of the protoplasm of the common 

 Amceba, a microscopic animal within reach of every microscopist, 

 and one in which the reticulation should be readily seen with the 

 proper optical appliances, if it exist. I do not know that any effort 

 has ever been made in this country to repeat this observation in 

 order to refute or to confirm it. The white corpuscles of human 

 blood are conspicuously reticulated after treatment with certain 

 reagents, and if the common Amoeba should present a somewhat 

 similar structure without having been subjected to the action of 

 a chemical solution, the fact would be of great importance and 

 interest. It would seem, too, that microscopists are not living ujj 

 to their privileges if they fail to heed a suggestion that may be of 

 so great importance. Y^'et so far as any prominent printed record 

 appears, the common Amceba has never been examined with 

 modern high-power objectives by competent microscopists having 

 this object in view. If such papers have been published, they 

 have not come to my notice. I am not claiming any merit on my 

 own part, for I am also one of those that have given no attention 

 to this attractive subject. I have never submitted the Amoeba to 

 the tests needed to demonstrate, for my own personal satisfaction 

 if for no other reason, whether or not the reticulum exists in its 

 protoplasm as Dr. Heitzmann says it exists. But that at certain 

 times in certain places within all animal bodies the structure of 

 protoplasm is reticular there can be no doubt. That the reticulum 

 exists at all times and in all places is another matter. 



But recently, while I was making a microscopical examination 

 of a sample of urine, a single scale of epithelium appeared under the 

 objective in a drop of the fluid, and was as perfectly and superbly 

 reticulated as could be desired by the most ardent advocate of 

 the theory. The cell had had no treatment except what may 

 have come from its soaking in the urine, yet the net- work of its 

 protoplasm was perfection, and its prominence must have forced 

 itself upon the attention of any microscopist. But thousands of 

 epithelial scales may be studied in as many samples of urine, and 

 not another found in this beautiful condition. 



In reference to the common Amceba, although I have never yet 

 studied it with the reticulation of its protoplasm in mind, I have 

 recently had the satisfaction of examining a favorable specimen 

 of the allied Pelomyxa villosa Leidy, in whose ectosarc the reti- 

 culum of the protoplasm was as perfect and as conspicuously 

 marked as in the single epithelial scale just mentioned. Pelomyxa, 

 is a common Rhizopod in this locality (Trenton, N. J.), but it is 

 usually so gorged with food, with sand grains or with other 

 opaque particles, that its body is almost black by transmitted 

 light, and therefore unsuited for such a purpose as a search for 

 protoplasmic reticulations. But this particular individual was 

 without these obscuring elements, being almost transparent, and 

 fortunately with the protoplasm of the ectosarc so conspicuously 

 reticulated as to obtrude itself upon the microscopist's notice. If 

 the softer and coutinuously flowing endosaro had been sur- 

 rounded or enclosed within a delicate net of cords, the reticula- 

 tions could not have been more apparent or more distinct, becom- 

 ing even more conspicuous when this external coating flowed out 

 to cover a newly produced pseudopodium. The meshes of this 

 beautiful net were angular, and the living threads that formed 

 them were rather actively contractile, the meshes becoming nar- 

 rowed and elongated during the animal's movements of progres- 

 sion. The greatest length of perhaps the largest space was, during 

 quiescence, about one six-thousandth of an inch, the smallest 

 being probably about one-third of that size, although careful 

 measurements were not made of either of these. 



There can be no doubt that at least at times the ectosarc of 

 Pelomyxa villoma is formed of reticulated protoplasm. That it is 



