Journal of Applied Microscopy. 



If the latter, make the preparation 

 either by germinating on the elide or else 

 in a manner commonly used for the 

 study of amoebae, and introduce the 

 staining medium under the cover glass. 

 Study while coloring and if desired, af- 

 ter complete staining of the plasma has 

 taken place, the staining solution may 

 be removed and the preparation either 

 studied living or fixed and made into a 

 permanent mount. 



^ The following stains may be used; the 

 first four have given me the best re- 

 sults: Methylen blue, malachite green, 

 violet Dahlia No. 170, methyl violet, Bis- 

 mark brown, cyanin, fuchsin, safranin. 

 It will be well to try Congo, which is 

 said not to be poisonous to protoplasm 

 even in strong solutions. The solutions 

 of these substances must be made ex- 

 tremely dilute (from 1-10,000 to 1-100,000) 

 and they should never be acid, but either 

 neutral or only slightly alkaline. 



These stains may be made with serum 

 and normal salt solution as well as with 

 water. Some of these stains will also 

 stain the neuclei, but none of them will 

 give the neuclear differentiation to be 

 had with the carmine and aniline dyes 

 applied in the usual ways after the Plas- 

 modia have been properly fixed. 

 To he continued. 



Platinum 

 strating 

 Muscle. 



Chlorid for 

 the Fibrils of 



Simon Henry Gage. 



Demon- 

 Striated 



Since the great monograph of Botv- 

 man* on the structure of muscle, the 

 fundamental facts presented by him still 

 ■are the ones represented in the best 

 modern text-books, although in some de- 

 tails there has of course been consider- 

 able modification. 



If one consults this monograph, or a 

 later monograph or book on the histology 

 of muscle, one can but be impressed 

 with the fact that there is a great pre- 

 ponderance of discussion upon the struc- 

 ture in lower forms, insects, fishes, and 

 amphibia. This is true, although the 

 book may be entitled " Human Histol- 

 ogy." 



If one seeks for methods to demon- 

 strate the various appearances figured 

 and described, it will be found that it 

 frequently requires days, weeks, or even 

 months, to get the preparations ready 

 for study. For the investigator who is 

 carrying on several pieces of work at 

 the same time, this may not be a draw- 

 back; but in the case of the teacher with 

 classes having but a limited time for 

 work, he must prepare material a long 



time in advance, and thus the students 

 be deprived of the actual personal expe- 

 rience which they can alone obtain by 

 taking every step themselves, or some 

 method must be devised which shall be 

 both certain and rapid. Owing to the 

 constant effort of laboratory teachers, 

 every year adds to the list of such rapid 

 and excellent methods. In my own field, 

 where mammalian histology and embry- 

 ology are of principal importance for my 

 laboratory students, there is a constant 

 effort to find methods applicable to such 

 animals in the published accounts of 

 others and by personal experiments. So 

 much effort is made because, while the 

 type may be the same in different ani- 

 mals, the details of structure are often 

 markedly different in the different 

 forms, and it seems hardly fair to stu- 

 dents to show them only insect muscle, 

 for example, and lead them to assume 

 that the appearances are exactly the 

 same in mammals. 



In studying the tissues of animals, one 

 of the greatest needs is some means of 

 isolating the cells or structural elements 

 so that details of form and structure 

 may be made out with certainty, and the 

 confusion arising from overlying or un- 

 derlying cells avoided. While making a 

 series of experiments on different media 

 for dissociation, it was found that plati- 

 num chlorid in a one-tenth per cent, 

 aqueous solution (platinum chlorid 1 

 gram, water lOOOcc-), acting from two to 

 twenty-four hours, gave most beautiful 

 preparations of the longtitudinal stria- 

 tion and the fibrils of mammalian 

 muscle. In many cases, if the teasing 

 was thorough, the fibers appeared like a 

 skein of thread, and frequently the fib- 

 rils were detached from the bundle, thus 

 affording opportunity for their special 

 study. 



The method has been applied to mam- 

 mals (man, horse, dog, cat, sheep, rab- 

 bit, guinea pig), amphibia, fishes, in- 

 sects, and cray-flsh. It is well adapted 

 to all, but more especially to the mam- 

 malian muscle, where the demonstration 

 of fibrils and longtitudinal striation is 

 more difficult or requires more time than 

 in the lower forms. t 



♦Phil. Trans. 1840-41, pp. 457-501, 4 plates. 



tMany good dissociators for special pur- 

 poses have been devised, but so far as I 

 know there has been no generalization of 

 the fundamental principles which would 

 serve as a guide in case one had not access 

 to the special liquid described. In a series 

 of experiments to see if there was not some 

 underlying principle, the writer came to the 

 conclusion that, while a given detail of 

 structure or a given kind of cells might be 

 more clearly demonstrated by one method 

 than by another, yet the generalization 

 seemed justified that " Any medium which 

 fixes a tissue well may be used to Isolate 

 its structural elements if employed in 

 a proper dilution (about one-tenth the 

 strength used in fixing) and allowed to act 



