LITERARY NOTICES. 



117 



layers thick before the formation of the 

 ridges, and become single again over these. 

 ... By the intersection of the ridges, pits 

 are left, which are the gland-pouches." The 

 " ovoid " cells are first specalized and later 

 the central cells, the latter alone being con- 

 cerned in the formation of pepsin. 



The third article is by Professor Martin 

 and Dr. W. D. Booker. Its subject is " The 

 Influence of Stimulation of the Mid-Brain 

 upon the Respiratory Rhythm of the Mam- 

 mal." Having found that chemical stimu- 

 lation of the mid-brain of the frog caused 

 accelerated or tetanic inspiratory and im- 

 peded expiratory movements, experiments 

 were made on rabbits to see if the same 

 phenomena were exhibited by mammals. 

 By an ingenious arrangement the animal was 

 made to breathe into a jar, the aperture of 

 which was covered by an elastic membrane, 

 and throuo;h a connecting lever was made 

 to record, on a revolving cylinder, all the 

 respiratory movements. The stimulus ap- 

 plied was by means of electrodes, connected 

 with a secondary coil of a Du Bois induc- 

 tion apparatus. The current from a single 

 carbon-bichromate cell was sent through the 

 primary coil. 



Reference must be made to this memoir 

 for further details regarding the experi- 

 mental methods employed. The general 

 results are summed up as follows : " There 

 lies deep in the mid-brain of the rabbit, 

 beneath the posterior corpora quadrigemina 

 and close to the iter^ a respiration regulat- 

 ing center, similar to that in the corpora bi- 

 gemina of the frog : electrical stimulation of 

 this center causes accelerated inspirations 

 finally passing into tetanic fixation of the 

 chest in an inspiratory condition, and cor- 

 respondingly diminishes or altogether in- 

 hibits expiration." 



The paper of Dr. I. Edmondson Atkin- 

 son, on the botanical relations of Tricophy- 

 ton tonsurans, details some very careful 

 experiments in cell-culture made in order 

 to determine whether excessive polymor- 

 phism existed among these lower fungi. 



Dr. W. K. Brooks closes Part I with 

 a memoir entitled "Preliminary Observa- 

 tions upon the Development of the Marine 

 Prosobranchiate Gasteropods." For material 

 the author studied two common marine snails 

 from the first segmentation of the egg to a 



stage when it emerges with its full class 

 characters. Among other things he shows 

 that, while there is no stage that can be 

 considered as a specialized gastrula, there are 

 presented at different periods of its develop- 

 ment all the phases in the formation of a 

 gastrula ; and also that, while the gastrula 

 stage has disappeared, the gastrula form 

 persists. 



Part II commences with a memoir by 

 Professor Martin and Edward M. Hartwell, 

 on the respiratory function of the internal 

 intercostal muscles. The authors show how 

 conflicting are the opinions regarding the 

 particular mechanical work done by these 

 muscles ; and how impracticable it is to 

 decide by a simple mechanical study as to 

 whether these muscles are rib-elevators or 

 rib-depressors. Dogs and cats were used in 

 their experiments, which show that the mus- 

 cles in question are expiratory in their func- 

 tion throughout their whole extent. 



The next paper, by Isaac Ott, M. D., en- 

 titled " Observations on the Physiology of 

 the Spinal Cord," is an account of the au- 

 thor's investigations of the secretory func- 

 tions, vaso-dilator centers, rhythmical func- 

 tions, genito-urinary functions, and path of 

 secretory and inhibitory fibers of the cord. 



On the " Effect of Two Succeeding Stim- 

 uli upon Muscular Contraction," by Henry 

 Sewell, Esq., is a paper which affords an ex- 

 cellent example of how minute and exact 

 experiments should be conducted. Among 

 other interesting facts it is shown that a 

 "given maximal stimulus stirs up the un- 

 tired muscle to a more powerful contraction 

 when it has been preceded by the excite- 

 ment ordinarily producing contraction." 



In the "So-called Heat Dyspnoea," by 

 Christian Sihler, M. D., is an attempt to get 

 at the causes of the increased respirations 

 in a dog, when it is subjected to a tempera- 

 ture warmer than its own body. Finding 

 previous experiments inconclusive, the au- 

 thor not only repeats those of Goldstein, 

 but details a number of new ones. His 

 conclusions are : 1. That Goldstein's experi- 

 ment with the tube is inconclusive ; 2. The 

 increased respiration following exposure of 

 the animal is due to two causes, skin stim- 

 ulation and warmed blood ; 3. Of these, 

 skin stimulation is the more powerful ; 4. 

 Apnoea can be produced in heated animals, 



