226 



SCIENCE. 



[Vol. YI., No. 136 



branches, which themselves repeatedly branch, and 

 are closely covered with scales. A further examina- 

 tion shows that this is the universal rule with the 

 species, no normal inflorescence developing. The 

 adventitious inflorescence always bears a definite re- 

 lation to the position of the parasitic roots: that 

 portion of the stem which produces roots, always pro- 

 duces flowers; and the greater the number of the 

 former, the larger is the number of the latter. The 

 stem proper dies away soon, not only between the 

 inflorescence, but also in the flower-clusters them- 

 selves. The flowering branches establish direct 

 structural connection with the host plant. When 

 this is accomplished, the scales upon the branches 

 often contain considerable quantities of chlorophyl. 



A short paper by Prof. B. G. Wilder was read on 

 the subject of the serrated appendages of Amia. The 

 view held by Sagemehl and Kamsey Wright, that 

 these organs are accessory respiratory organs, is found 

 to be sustained by the experiment which Professor 

 Wilder performed on the living animal; and his con- 

 clusions are, that, while the appendages have no func- 

 tion at the present day, it is quite probable that 

 their development and paleontological history are 

 well worth careful study. 



Dr. C. S. Minot discussed the subject of the rela- 

 tion between histological differentiation and death, 

 and arrived at the conclusion, that the only rational 

 explanation of the fact that animals and plants un- 

 dergo progressive decay, as well as a progressive 

 development, is to be found in the fact that highly 

 differentiated structures, or organs, have lost the plas- 

 ticity of embryonic tissues, and are incapable of 

 renewing themselves when once worn out: incon- 

 sequence of this, death is the price paid by the higher 

 organisms for their advanced organization. 



In another paper, on the moi-phology of the supra 

 renal capsules. Dr. Minot made an important ad- 

 dition to our knowledge of the structure of these still 

 problematical organs. The structure of the capsule 

 is similar throughout. Tliere are masses and cords 

 of cells which are in radial lines externally, but which 

 are irregularly arranged internally. The cells of the 

 medulla and cortex are almost identical in appear- 

 ance in a six months' human foetus, on which ac- 

 count it is diflicult to admit a double origin for the 

 capsules. The same speaker presented a paper on a 

 new membrane of the human skin, which hehomolo- 

 gizes with the epitrichium of the lauropsida. It is 

 situated outside the horny layer, and is entirely dis- 

 tinct from it: an extension covers both hairs and 

 glands. It probably causes the vernix caseosa by 

 retaining the sebaceous secretion. 



An interesting and important paper on the embry- 

 ology of Onoclea and other ferns was contributed by 

 Mr. D. H. Campbell of Detroit, the details of which 

 cannot be given here. Drs. D. E. Salmon and T. 

 Smith of Washington, D.C., read a paper on a new 

 chromogenous bacillus (Bacillus luteus suis). This 

 form is non-pathogenic, and was found in the peri- 

 cardial and peritoneal fluids in swine killed for the 

 purpose of stwdying the swine fever. When grown 

 in a meat infusion, the liquid becomes pale straw 



color, then orange with a greenish tint, soon chan- 

 ging to a wine red. The pigment when obtained pure 

 is insoluble in alcohol or ether. An aqueous solution 

 is decolorized by adding an excess of strong HNOg, 

 or HCl, but reappears on neutralizing with potassium 

 hydrate, or ammonia. 



The relation of ovary and perianth in the develop- 

 ment of dicotyledons was discussed by Prof. J. M. 

 Coulter. A most simple and important character of 

 systematic value was discovered in the study of the 

 embryology of the dandelion ; and, on comparing with 

 the same embryonic stages of a large number of fam- 

 ilies, it was found that the character of superior or 

 inferior ovary was the first recognized. In the case 

 of an inferior ovary, the protuberance, which is to 

 develop into the flower, is arrested in its axial de- 

 velopment, grows perpendicularly into a collar (the 

 nascent floral envelopes), and soon there appears an 

 external constriction distinguishing the floral enve- 

 lopes above from the ovary below. In the case of a 

 superior ovary, the axial development is continued, 

 and there is no external constriction. On such a 

 basis the Compositae stand at the head of the list, then 

 Umbelliferae, Rubiaceae, etc. The second group, that 

 of a superior ovary, includes Leguminosae, Scro- 

 phulariaceae, Labiatae, etc. A paper on the struc- 

 ture and functions of the sphaeridia of the Echinoidea 

 was read by Dr. Howard Ayers. The observations 

 of Loven were supplemented by a large number of 

 structural facts, which, besides allowing of greater 

 accuracy in determining the function of these pecul- 

 iar organs, furnish an example of a highly specialized 

 organ in this group that is comparable to the otolith 

 sacs of Synapta. The following papers were read, of 

 which extracts cannot be given here : ' The impor- 

 tance of individual facts of environment in the forma- 

 tion of groups of animals,' by Prof. J. B. Steere; 

 ' On the morphology of the carapax and sternum of 

 the decapod Crustacea,' by Dr. H. Ayers; 'Notes on 

 some injurious fungi of California,' by Prof. W. G. 

 Farlow; 'On the evolution of the lungs,' by Dr. C. 

 S. Minot. 



THE LIMITATIONS AND VALUE OF 

 HISTOLOGICAL INVESTIGATION.^ 



While choosing a subject relating chiefly to micro- 

 scopic structure for the address before the section 

 of histology and microscopy, I wish first to discuss 

 briefly what constitutes a complete knowledge of 

 structure, and what are the limitations and value of 

 this knowledge. The knowledge of structure depends 

 greatly upon the coarser, i.e., the macroscopic rela- 

 tions. There is no magic in the microscope; it is 

 simply a tool, nothing more. It is as illogical and 

 hopeless to expect to understand the structure of an 

 organ from what can be learned of it under the mi- 

 croscope alone, as for a geologist to expect to under- 

 stand the topography of a continent by studying the 

 sand of its sea-shore. 



1 Abstract of an address delivered before the section of mi- 

 croscopy and histology of the American association for the ad- 

 vancement of science, at Ann Arbor, Aug. 26, by Prof. B. H. 

 GrAGE of Cornell University, vice-president of the section. 



