( 365 ) 



upon the tracing of the deep, sigh-like respiration, mentioned above. 

 Always the deep inspiration sets in at the beginning, the suppression 

 of the expiration lasts till the stimulus ceases. Usually the stimulation 

 causes also stretching of the neck. 



It proves that it is necessary to control the tracing of the thoracal 

 movements (registered with the pneumograph of Marey) by the 

 tracing of the changes which the pressure of the air in the trachea i) 

 undergoes. The quick respirations then appear as violent gasps, 

 causing very extensive movements of the lever, inspiratory as well 

 as expiratory. 



The stimulation ceasing, the inspiratory eft'ect still continues. After 

 a strong stimulus a few quick respirations take place followed by 

 deep inspiration. 



The effect of the excitation of the N. tricjeminiis upon 

 the Respiration. 



Equally charactei'istic is the effect of the excitation of the first 

 branch of the N. trigeminus upon the respiration. 



"We examined the N. frontalis and the N. lacrymalis of the ramus 

 ophthalmicus Nervi trigemini (Fig. 3 r. lacr. N. V.). As yet we 

 will not speak of the N. ethmoidalis and the N. naso-ciliaris. 



Even tlie weakest currents (12 cm. distance between the coils) 

 cause quick, violent gasps, inspiratory as well as expiratory, such 

 as we mentioned previously, in speaking of the optic Nerve. The first 

 of the quick respii'ations may be an expiration, in general this is 

 not the case. The tracing now obtained, forms however a perfect 

 contrast to that of the respiration produced by the excitement of the 

 optic Nerve; the effect is not characterised by the sigh, the maximal 

 inspiration followed by suppressed expiration does not exist. On the 

 contrary, the inspiratory position of the thorax slowly increases. The 

 stimulus having ceased, the slowly extended, but now distinctly inspi- 

 ratory position of the thorax changes suddenly and makes place for 

 a forced expiratory position, though the quick respiration continues 



') For this purpose the vertical tube of a hollow T-canule is introduced into the 

 trachea. The air enters freely through one horizontal arm, the other is connected with 

 Marey's drum. The tracings show only the cj^uick changes of pressure of the air 

 in the trachea. Continuous conditions, such as a permanent inspiratory or expiratory 

 condition of the thorax are registered as zerolines, and slow variations of pressure, 

 even if they are noticeable, are registered (one of the legs of the T-canule being open) 

 in an incomplete manner. 



